Yamaha RD421LC  
               - Engine

All content copyright Jon Wallis 2009-Present.

No photograph or text from this article can be reproduced without prior permission from Jon Wallis.  As such all text on this page is protected by enforceable copyright.

Regarding the pictures on this page - Jon Wallis either owns the rights to these pictures, has permission to use these pictures or has taken every step possible to contact the owner of any borrowed pictures – As such all pictures on this page are protected by enforceable copyright.



Since the original engine wasn’t in it’s first flush of youth and even with my corrosion removal plan (the vinegar bath) proceeding apace for the transmission, deep down I knew that it probably wouldn’t be the ideal power plant for this bike as this one would need something ‘more’...

With that in mind, I sat down and began to formulate a plan of what I actually wanted as the motive power this bike... and as it took shape, it became obvious that it was going to be quite an engine... and when embarking on big engines with lots of new parts you need deep pockets, so I just had to be work out how to fund it... this meant selling off the spare LC and then raiding my piggy bank... at the very least!

Around the same time as I was attending to the bottom end I also took the Athena head to an Alloy Welding company to have the water outlet angle ‘fixed’.

As standard the Athena kit has an outlet that runs straight out to the front, i.e. directly into the radiator when fitted to a bike; it’s perfectly fine on the Banshee of course. On the OEM YPVS and LC engines there is a thermostat housing setup built into the top of the OEM head, and the outlet from that exits straight up.

Since (as ever) I wanted to do this engine ‘right’, I decided that I had to engineer a proper solution to get the outlet to run up at 90 degrees to how it was ex-works, and it had to be done in a small amount of space.

Some builders had cut and threaded the old outlet, then fitted an oil or plumbing fitting; some had welded and some had used 90Degree bend hose and then spaced their radiator forward a little. I opted for having an alloy 90Degree outlet Tig welded on to a the original outlet once it was cut down. This appeared to be a simple solution, and would cost much the same as the other options.

When I picked up the head I felt it was akin to the infamous ‘Curates egg’.... i.e. it was ‘good in parts’. The welder made a nice outlet for me on the lathe and then had welded it on with some unattractive welds, and the head was not quite ‘flat’ with a smidgen of ‘rock’ that could be felt in your fingers when placed on a flat surface; nothing that could be seen of course. The welders told me that they did clamp it down, but there isn’t much to these ‘cool’ style heads since there is no solid dome area, hence it is more like a cage or open box so warpage is always a risk. Initially I worried that it might need skimming which would be a disaster, but Roger from Wicked advised me to fit it and then torque it again once it was hot. I did this as so far it has been fine. Phew!

Everything looked good so I started on the transfer port matching which is needed as the Athena cylinders have a much larger transfer port than the original 250/350 cylinders used on these cases. You don’t have to do this, but I learnt early on (from a cop that caught me speeding on a souped moped no less) that anything that impedes flow of the inlet charge to the cylinder is usually a problem; and this area could be deemed a restriction, so it was dealt with.

This was done with a set of burrs in a Dremel which made short work of cutting the cases to match the transfer ports after the shapes and sizes were transferred using a gasket, that had previously been carefully cut to match the cylinder, as a template.

The port matching work took about 2 hours from start to finish and whilst it isn’t hard work as such, it is painstaking as you need to be careful not to remove too much material. I now have awe for the tuners who do this stuff daily... it takes sooo long!

The amount of material that needed to come out by the time the depth and radius was corrected left piles of chips on the bench, so there is definitely extra CCV (Crank Case Volume) in there now and the air/fuel charge will get into the cylinders easier as well as the transfers are about 1.25 times their original size, so seems like a bonus on all counts.

FYI: The chips are actually quite cool, they’re not that sharp like normal swarf from a lathe or drilling, more like tiny chunks and so can be swept up off the engine cases easily.

The rough work was followed up with a clean up with a sanding roll but the finish is not that smooth, some say that turbulence is good for torque, some says it should be smooth... of course, there are a lot of ‘old wives tales’ in tuning!

With the head back and the other engine parts now arrived, the engine build up could start. It is worth noting that this engine started life as an Aussie spec ‘1GAxxxxxxxx’ unit, which means it began its life as a 250. I bought from a wrecker as a mostly intact bottom end, as amazingly it had no case damage. Sadly pretty much unheard of these days over here in Australia (and probably elsewhere too!).

Whilst waiting for the head to come back the bottom case half had a clean up in the blasting cabinet, then both cases received a couple of very thorough cleans and rinses and I splashed a bit of paint on the top case.

In the top half I added a 31k rev counter drive as I wanted to use the LC clocks, at least initially. These gears were quite easy to fit as the holes/fittings are already there in these later cases and I only needed to re-tap the bolt hole for the plastic tacho cable connector as it was full of crud/paint as it had never been used. Naturally I fitted a new clutch arm bearing and seal, as these are often worn and its simpler to do these now than later.

Next to go in was the brand new TSS +4mm crank (tungsten insert balanced and complete with 11 ball outers and peek coated mains) and I also added a full set of TSS uprated bearings to the rest of the transmission shafts, plus new shift drum bearing and an uprated shift shaft bush, and of course all new seals and new locking tabs from Yamaha where needed, the latter two as it just makes sense to renew it all when you have it all apart and have already done the other significant work and the upgrades.

Dropping the top onto the bottom after a smear of Threebond 1211 and its already starting to look like something useful!

Delving into the box of parts I received with this engine I grabbed out the clutch basket and checked the movement in the rubber cushions and found them to be sloppy... Luckily I have another engine so I robbed a better one from that, with the view that I might change up to something more sexy if the standard item doesn't cope with the power. The better of the two baskets had some notches on the tangs of the basket of course... Don't they all by now!? So out with the trusty Dremel and I tidied up the 'teeth'. I wasn't aiming to make them flat as such, just knock off the high points and steps to stop the plates catching in use. It’s not a perfect solution, but it gets a bit more use out of these old baskets.

New banshee clutch plates were added along with a set of new '10% stronger than stock' springs. I not convinced these plates and springs will cope with the power, but I had them already and decided to start there and see how it goes. Amusingly, when I bought the clutch plates I was told I was getting a good deal as I was getting the banshee plates which were 'asymmetrically the same' unlike the normal plates, and hence 'easier to fit'. When I finally opened the box over a year later they are just normal plates... No huge deal to fit of course, but mildly amusing that I didn't check and mildly annoying that I may have paid for something I didn't get, how green I was back when I was doing my original orders... Hmm... Anyway my mistakes aside... I soaked the plates in oil and fitted up the parts and then to ensure the clutch pusher doesn't weld itself to the ball I fitted an aftermarket clutch pusher with a pancake bearing, again from Wicked.

Continuing with cool aftermarket parts I also fitted one of the RDLCCrazy natty allen key drain plugs as well in the hope I can drain the oil without having to remove the pipes, sure my pipes are pretty fat, but one can hope!

To finish off the oily bits I added a NOS clutch cover. The NOS term should be used loosely really as this part is the Banshee version, Ok, yes it’s pretty much identical to the YPVS really and it’s still available new from yamaha. These covers come bare and I fitted a new water pump seal and bearing and an uprated waterpump impeller that has a higher rate of flow to the standard item, and to top it off a new OEM dipstick + o'ring seal.

One thing about these covers and maybe also any other cover you might be re-fitting if you have the waterpump off... Look up the pump towards the engine and see if it's blocked... On mine the casting flashing wasn't too well removed (seems this is done later by hand at the factory during engine builds) so I got out the Dremel and the burrs and opened it up fully... Im fitting a higher rate pump and it would be silly to have a restriction stopping it doing it's good work.


I decided that I wanted to fit a later YPVS motor into the LC frame but instead of the YPVS top end I wanted it fitted with the Athena top end. These Athena barrels were developed for the Banshee sports ATV and are 68mm instead of the usual 64mm, the extra diameter leading to a cc of 392cc. However, I wanted a little bit more, so also fitted a +4mm stroke crank and with that into the equation gave the motor 421cc, a significant upgrade on the standard bikes 350cc.

Moving to these cylinders meant losing the YPVS and whilst this means a less smooth power delivery than the later bikes, it is more in keeping with the original LC motor which didn’t have that setup. Whilst I wasn’t looking to tame the motor as such, I did hope that adding cc’s would give back some low down torque to the motor might lose without the Powervalves.

Then... DISASTER!!!! At this point I realised two things.... They meant that I had no option but to tear down the whole engine again... Deep breath....(Say to self ‘close eyes and think happy thoughts’)!

Ok, it happens of course... We always hope we know best and what we are doing but sometimes stupid things, not the best light, working at the end of the day and such like mean that things get missed.... no excuses, and i’m sure the Pros do it too...

So the two things that meant that I had no option but to tear down the whole engine again...

No 1 - As the engine was done, I was clearing up all the tools and old wrappers from the new parts etc etc. as I didn't have enough time to fit the motor that day. My mind and bench being cleared ready for the next chapter of this huge Airfix kit, namely; the exhaust.

With that in mind I pulled from storage and opened up some boxes for the exhaust parts and pulled some flanges out and lo ‘n behold inside the bag of flanges, springs and o’rings were two lozenge shaped rubber bungs that should have been fitted to the underside of the cylinders... Arrrghhhh! not happy...!

Its tempting to blame the packer (Roger! LOL), but it's actually my fault as I had him seal up all the parts gathered together in bags so I didn't lose anything when transporting this lot home from LA as the wo(nder)ful guys at the TSA have a habit of opening up checked baggage that looks 'different' and then to find to the thing they want to look at inside, they chuck bits of the contents all over the place... sigh... i’m not a terrorist, just an urban guerrilla with a loud pipe on a sunday morning...

As I definitely didn't want to lose any of the small bits in the travel process, things were bagged and sealed. And it worked well in fact as TSA did open up one of my bags, but it wasn't the one with the two bazooka shaped exhaust pipes for this bike, instead it was the one with the CR250 cylinders... who knows why?! They ripped open the bubble wrap, cut the box and left the cylinders all loose in the bag, they also left the handles unclipped on the bag so when it was pulled from the plane by a single handle the side of the bag was ripped open, luckily nothing fall out of the 8inch diameter hole... So, yes, I was right to have Roger seal up the bags and have parts sealed in boxes etc. But whilst I was right about travel... I wasn’t right to not check all the bags thoroughly before I built the engine.

I guess most bike people won't know what these bungs are as we have RD/RZs not Banshees. The Banshee cylinder isn’t solid at the bottom like the YPVS cylinders and instead has a long hole with this rubber bung pushed in it. The Athena cylinders come with this hole roughly cast and it needs to be ground out with burrs to match the bungs, that work is part of the ‘$40 fettle’ that Wicked does on these kits, well worth it I reckon. Fitting these is simple and I added a little bit of 1104 just to be sure they stayed in place once it was all fitted.

No 2 - The big one... I might have got away with the bungs not being fitted, unlikely but you never know, however I hadn’t noticed but when fitting the top engine case, the stator side seal had slipped and the dropped off the crank... School boy error of course... and I should have noticed that but I just didn't look at that side at all during the build... Im still kicking myself. Live and learn.

So I whipped it all apart, in about 20mins... and it all went back together quickly after the 1211 was cleaned off the case halves, this time remembering the crank seal and also sorting out a slight rocking motion I had in the cases on one of the new bearings which I had played with the first time, but this time totally eradicated.

Phew crisis averted.... and looking more like an engine!

Im happy to say that I believe that Roger was right, the slight (and it was very slight) warpage to the head would easily have been taken up by tightening the head bolts. To be honest looking at the casting, it really is just a cover that holds the domes in position and is very recessed for water to flow thru, that means it’s like a 3 sided cage and being alloy it’s quite malleable and I’m sure after a few heat cycles it will just stay the shape its now clamped in, although as I said it was only very slightly out.. of course starting it with water in would soon tell the full story...

Fitting the head... Well let’s just say its a b$%@#$*d of a job if you don't know how to do it... The thing has 3 sets of o-rings and two free floating domes... all that means you've a lot of loose parts to fall out once you turn it over... Discretion being the better part of valour, I emailed Roger....

He laughed and told me the trick is to grease the o’rings to hold them in place and set the domes up first on the engine, which you should have already levelled so the cylinders are horizontal or the domes will just slide off... He is right, it’s a simple job once you know that, but fiddly to get right as everything needs to be set up almost spot before you gently slide the head over the domes. The main advice is to try not to pinch an o’ring... How will you know if you have? Time will tell, when you run it...

Athena provides it’s own head bolts and which I used with slightly thinner washers as Roger advised me that the studs are really only just long enough as they are, and every little bit of extra thread helps when they're torqued.

As you can see Athena doesn't list the order number for the bolts on the head so I had to write them on with pencil. Easy to remove of course.

Moving on to the top end I fitted the Wicked supplied Wiseco 573 'Blaster' pistons which have an offset wrist pin location compared to the Banshee/RD/RZ. These were chosen as I didn’t want to run a spacer plate with the +4mm crank and these pistons helpfully have enough offset to cope with the long throw crank, i.e. +2mm.

There are lots of reasons why you may chose to use, or not use, a spacer plate, so another person’s mileage may vary with that decision. Most of that decision is to do with port heights, although some have made chosen the cheaper route of course. I wanted to do this right and Roger@Wicked scoured the sets of cylinders he had to find ones with ports in places that suited what I wanted from my engine, i.e. Torque, as the castings can differ over the product runs.

Sadly the Blaster piston isn’t wholly perfect as these pistons are very slightly too tall and will run slightly into the head if you just fitted them on a standard Athena setup. For tuning the domes in the Athena head are removable, and replaceable if needs be. When fitting these new pistons the domes in the head will need cutting to get the correct squish. I had this work done in LA as well of course.

Pistons went in with new little end bearings from TSS that came with the crank and I checked the ring gaps and using Wiseco’s specs they should be 0.27mm, and my not so great measurements have it at .30 so no chance of too much ring expansion at least, and not far enough out to worry about compression loss either from what i’ve read.

Dropping on the Athena 68mm barrels was easy and then it was time to fit the head....

Fortuitously my wife and I had planned to visit the USA for our holiday and since we were driving Route 66 (more on that elsewhere when I get time to write it up) we had a car and would end the holiday in LA. A few miles from Disneyland is a mecca for all things Banshee and RZ, Wicked Motorsport.

Whilst at Wicked I collected a full Athena kit, mild steel fat belly pipes for the larger cc engines along with Toomey silencers. I also added the Wicked Cross over manifold (to ensure the carbs would lift above the clutch arm) and Vforce III reeds which have been port matched to the intakes. Roger also supplied me a set of Wiseco pistons and cut the domes of the Athena head to accept these pistons and the throw of the +4mm crank. I also picked up a set of Wicked’s useful ‘clutch pusher’ and ‘shift helper’ upgrades.

A few more jobs before the induction goes on....

I finally got the remnants of the old water pump gasket off an old water pump cover plate I had on another engine cover and fitted it with a new gasket and the original bolts as they were still ok, rare i know!

Ideally I will fit one of the natty easy drain alloy plates but I don't have one and didn't want to leave it open to the elements any more than I have to so it was time well spent.

I also fitted the hose from the pump to the head, I used one of the silicone hose kits from RDLCCrazy and used stainless steel jubilee clamps I found in the local hardware store, Bunnings. These clamps have a smooth underside which is vitally important for silicone hoses as the type with the slots or the worm drive showing through will tear through your sexy and expensive silicone hoses in seconds... Been there and done that when building a turbo car years ago... So, Please buy flat backed ones if you have sillicone hoses, you will thank me for that tip!

To cope with the huge gulps of air needed to satisfy the appetite of this 'Mighty Motor' (for those with bigger engines these will seem small so maybe I should say 'mighty-ish'?! haha), I added Vforce3 reeds which were port matched by Roger to his Wicked Cross-over manifold when I was in LA.

I fitted these with the bolts provided and the gaskets from the Vforce kit, but added stainless washers on the stainless bolts. I did have to shave a small edge off the washers for the lower bolts as the alloy is close to the bolts there. I always feel its better to run washers on painted or alloy parts...

These manifolds include the crossover tube inside the unit. They are two piece and CNC'd from billet of course. You can fit all sorts of carbs to these using rubber mounts which you specify when you buy the unit, and I don't yet have my mounts as I didn't know the exact carb plan when I was in LA so left the mounts ‘til later.

While you wait... A thought on costs....

Interesting thinking of costs and thinking about how much this bike will set anyone back who wanted to build one... Like restoring and rebuilding any and all RD/RZs, and more so if its mod’ed bikes, it's a life choice I reckon.... A normal LC is fine, but I wanted the RGV front n rear ends and also a faster motor... that plan just floated my boat I guess... I’m funny like that LOL! So, since I was mindful of budget, when setting out on the build I decided that to keep costs down (I am really not a rich man!) so not only would I go with tried and tested and proven mods and technologies, and I would also do as much work as I could myself, so as you’ve seen throughout the thread much of the chassis stuff was procured by me and via friends, and most of the work has been done by lil ole me... And yeah, I’ve done a lot of scouring the net for parts and services.

That said, the motor was always going to be costly, though in real terms not that much more expensive than converting my old 250 YPVS to a 350 it seems... For that build I needed to locate the 350cc cylinders, PVs, pistons, rebores etc etc, so the Athena kit I’ve used here works out at superb value for money, especially for the price/performance, but... to get the best out of that investment you can’t just blindly fit the old VM26 carbs, the old manifolds or the old exhaust pipes or the old ignition of course... they would strangle it! That’s where the costs really start to mount up.... While the balanced crank might seem a splurge to some, and yes it was about double the cost of a standard item I should say that I’d have fitted aftermarket pipes anyway and Wicked's are some of the best value (and tuned for this size motor), plus I already have sets of Gibsons and TSA (Kenny) on other builds.

To conserve my coin I did plan ahead and so bought most of these parts when i was in the USA earlier this year, and as such I saved a packet on post and I would advise anyone to do the same if they can, plus it was a revelation dropping in on Wicked when in LA! We had a good time and I got to ride bikes in LA traffic, who wouldn’t want that experience?! ...but i will say that whilst re-building any engine isn’t a cheap thing to do if done right, building one with so many new parts is certainly never going to be a low cost thing to do. But... I wanted to get around 80bhp, and this was the cheapest way to do it using proven off the shelf parts with mild mods. Plus it’s all new, I’ve been there before doing work on used bike engines or even just parts that sellers tell me are 'mint', and one mans ‘mint’ is another mans ‘trash’ I now reckon...

What people dont tell you is that actually some of the parts are cheapish though, high flow impellers ($60ish) and NOS side cases ($115) are cheap stateside, it’s just in places like the UK and Aus that we pay thru the nose for them, especially from Yamaha  Some things cost a bit but actually financially make sense, like the full Athena kit; US$720ish for new cylinders, head and pistons with top end gaskets etc seems good value when you consider buying new pistons and having a rebore for a standard 350. Of course I immediately ruined the good value as I also bought Wiseco's to avoid using a silly spacer plate, which added to the cost. But... $180 for the new pistons, and then $100 back on ebay for the never used Athena's... and now it starts to make a bit more sense again. I will agree that the cross over manifold and Vforce3's weren’t cheap items and they are super sexy 'bike bling', but they were cheaper than anywhere else I could find similar items back with uncle Wicked (like most of the engine parts I bought), but whilst not cheap perhaps, those parts were where the cash was best spent really as they help the engine to fly... the cost of the rest of the engine is pretty normal for the build and even the PJ34s are about $350 and come jetted close to what I need which is only double over some old used KR1S PWK28s that might not come complete, as I found out when going that route on the YPVS I did... sometimes new parts can save you time and money... I don’t advocate it for every item, but do the research, these things change over time.

What is perhaps funny to some who are reading this, is that I don’t feel this is an outrageous build. The 421 Athena is really just the start of the big cc engines with new cylinders and has been done plenty of times before. Whilst I was visiting Wicked, Roger showed me the upper end of the market... Billet CNC cases and single casting 600cc twin cyls and a bunch of other very cool stuff (even triples!) he had there for customer builds (and bear in mind that now fuel injection is on the horizon). With the big cylinders it seems that 150bhp+ is expected and can be set up for drag, race and all sorts depending on porting. The Banshee guys in the USA spend serious money for street race bikes and also for fun and this makes our normal bike builds look like chicken feed really, but it’s just a different market of course.

So yep, a few shekels were spent on this motor and more to go for sure, but it should be fun when done and I don’t intend to sell this bike, just use and enjoy it. Fingers crossed I like it when its done LOL

Moving forwards.... I gently placed the motor in the frame, partly to get it off my bench, but also as I need to work out where the last few pieces of the 'pipe puzzle' fit so I can get them welded and also to the hi-temp coaters whilst I concentrate on other things, you’ve gotta love a bit of parallel working!

I was always a bit concerned that the pipes would need a bit more custom fettling than just dropping on and bolting up as I have an LC not the later YPVS (which they were designed for), and the bike has Raask rearsets and they have to cope with the greater out-swing of RGV swinger.... A few variables in there then!

With this in mind, I ordered these pipes without the stingers or the rear hangers fitted. This also helped as I was bringing these pipes back from the USA in my baggage and to get them in the bag and still conform to the length of bag allowed on the international flights, plus I am sure they would have been damaged in transit if they were the full length. As it was they were short enough to be safely covered in bubble wrap and my dirty clothes (nice!) from the trip!

(For those who don’t know the Aussie airlines, when they aren’t on strike, are the most hard work when it comes to baggage size and weight, with stiff fines for non compliance... it wasn’t always thus, bring back the old days I say!)

These pipes are mild steel (tho Wicked now does these in stainless as well I think) and come with Toomey alloy cans. It took mere minutes and the pipes were on and held with cable ties... and, on the right they look and seem to fit well:

On the left its a different story I’m very sad to report... they foul the side stand and look close to the centre stand mounts, but of course, this was expected as these are fat pipes and the side stand would always be an issue as it’s very close in on the bike.

The side stand is an easy fix, just cut the end off the side stand stop switch actuator and then hammer a ‘dent’ in the pipe to accept the side stand ‘foot’. The centre stand... yes, I know, I know... few people agree with me, but, I quite like a centre stand on these bikes, yes I can use a paddock stand to adjust the chain but there is something of the older era about a bike with its own apparatus to lift the rear wheel off the deck!

'Ello Jon, Got a new Zeel...?'. A local guy (thanks Ant!) was selling an unused Zeeltronic VCDI-04 with controller just down the road and I figured that this would be perfect for the LC, and would mean that the PCD10V I was about to fit would then remain unfitted and could go on another PV project, always seemed sad to not be making use of the PVs functions of that unit, so all good.

I had actually been wondering how I would integrate the stator / rotor from the YPVS into the LC CDI and loom and had been thinking of using an LC setup and now this clinched it for me, as it would all fit like it it was designed to.

Fitted up the flywheel cover, and found it might make sense to use a cut down cover I have in my spares as the LC frame is a little bit of a tight fit with this engine. If I hadn’t had that, it would have meant more fettling to work that out... thats the sort of small job that takes so much time when doing specials, and it’s very hard to really show the volume of extra work / rework that ‘special builds’ keep needing over-and-over to shave parts to get them to fit.

I test fitted the gear lever on the rearsets and that worked well, and flushed with success then also test fitted a trick banshee Kicker I bought a while back on ebay.

With the Raasks it seemed like it might just knock about 1mm of the edge of the rear brake slightly but was otherwise is fine, but when I later tested the brakes I needed to raise the pedal and the kicker was firmly hitting the pedal. I could have ground some material off the pedal, but I didn’t like the idea, so instead reverted to a standard kickstarter.

So with the pipes held on with cable ties pending my further work to make them fit, it was starting to look a bit like a motorbike! Ok, this was an unnatural vision of progress... the pipes are not even close to being completed, the electrics are not connected and the bodywork was way off... but it did feel like I was getting somewhere!

I had already ordered a set of TSS uprated engine bearings, gaskets, seals, uprated water pump and a +4mm balanced crank with 11ball mains, along with a new Banshee clutch kit. These parts were waiting for me when I got home.

As usual when I build up an engine I started the engine rebuild by cleaning the engine cases and checking them over for damage.

With the lower engine I did the usual build up and then fitted all new kickstart idler gear and its washers and clips from Yamaha. I find the idlers on these old engines can be wobbly and this one was no exception. The parts are cheap enough to just replace, so I did. To get a nice positive shifting action I added a Shift Pro kit, some people might mock these, but I find I struggle to get neutral without one as I don’t ride the same bike daily so don't get to know it as well as id like and these seem to help with that, so i’ve fitted them to the RD/RZ engines i’ve done recently.

A quick 'How to' on these pancake bearing clutch pushers... Mine came from Wicked, but seems a few guys sell them now. Anyway, using the OEM nut and washer and adjuster rod in the new pusher, thread it so that about 2 threads protrude on the outside of the nut. Hand fit the cover (ie just hold it flat on the clutch, don't hold the nut or the pusher, let it be loose) and move the clutch arm, you will feel when it takes up the slack and starts to move the clutch, when that happens the arm should be at the arrow mark. If not, readjust the adjuster nut until it is and then lock it off by holding the new pusher from the back (it has flats for this) and winding the nut against it. Job done.

Ok, not quite as simple as OEM, but easy enough when you get your head round it and these units provide peace of mind from the fact that it's got a bearing in it so the pusher isn’t captive to the clutch cover and so it stops the single large ball bearing in the system welding itself to the rod as the clutch cover is no longer captive to the pushing mechanism hence reducing heat. Without this mod sometimes the heat build up can lead to the pusher rod and the ball bearing welding themselves together. Not good of course... $30 fix... Seems simple insurance.

Im going to run this bike on premix for now, well at least until TSS sorts out the new oil pump plan for their 421 and larger engines. So in the meantime I added an OEM blanking plate, this is an OEM banshee part and cheap enough from Yamaha not to need to go aftermarket.

The new clutch cover was fitted with new gaskets and also a full stainless allen head bolt set from Yambits, much cheaper than anyone else who does these. The clutch cover was also fitted with a stainless steel Yamaha disk which I bought for when the window gets cut into this cover... But that remains a future mod as I cant bring myself to cut open that lovely new OEM Yamaha engine side cover!

I decided that as I want to get this engine in the bike to sort out my pipes that I didn't want to bother messing with stator and flywheel until it was in. Leaving these parts off reduces the dead weight of the engine a little.

Then fitted up the two water drain bolts on the sides of the cylinders using stainless bolts and fibre washers... Ok a quick test... How many of you didn't notice they were missing in the previous posts/pics?! LOL

(Some people have suggested using stainless bolts in an alloy cylinder is a mistake. I did use lots of copper grease and will keep an eye on these, but maybe my advice to others is to use something else)

(I should also add at this point that I fixed the clutch arm clamp in case anyone notices that is incorrect in the early pics of the engine rebuild, I always seem to put it back on the wrong bolt for some reason and then have to swap it...)

At the same time I also looked at my sprockets and the engine side is an offset item supplied by NK Racing with the swing arm conversion parts, and it is way out of line and obviously the wrong one when fitting a YPVS motor to the LC frame. I believe its for the Original LC motor when using the RGV swing-arm. It’s a shame NK didn’t tell me that, I could have saved some money, perhaps he didn’t know?

Because I transported my pipes back from the USA without the stingers, this left me with a few things to do...

- Weld on the stingers (obviously)

- Weld on the flange for the can

- Weld on the mounting brackets

On the face of it these seem simple enough, but there are actually a lot of variables in all that and a number of different ways / options to get the pipes in place. E.g. The slant of the stingers can follow the line of the lower part of the belly, or the upper... Or go it’s own way... The angle towards or away from the bike can follow the belly or not, and you need to be aware that the further away in degrees at the join with the belly translates to more distance for the tail pipes from the wheel and no one wants the bike to look like it has it’s legs akimbo!

The brackets that the pipe hangs on are another thing... They need to be angled of at either the pipe or part way down the stinger, as the pipe body is a different angle to the rearset or... Do what some guys have done and use different mounts elsewhere, like on the pipe belly... That was very tempting as I like a clean look, but my bike isn’t that trick and as I do want to keep the passenger pegs, I decided that I may as well use the original mounts.

After looking at a lot of exhausts on line, tons of bike photos and hours sat in my garage and playing with the pipes, I cut the stingers, held things in place by using countless cable ties and tape and decided to run the stingers parallel to the lower line of the belly as I liked that look, and also follow the outer line of the belly (when viewed from above) but keeping the cans away from the swing-arm. All that said; It ended up like this:

And so with one side done, I then had to get the other side to not only mirror the first side in how it fitted but when it was complete and the cable ties undone it needed to fall to the same point and be level... No pressure then! After some tacking and testing and I was set... A few more tacks and its solid... a few days later sent them for ceramic coating in silver. Exciting times!

The Athena head isn’t like those of the LC or the YPVS, in that it has no integrated thermostat unit and no provision for the temp sender. So whilst that’s not ideal, there are options:

1, Roger from Wicked suggested I drill and tap the head to fit the sender. That would have been a great idea as the temp sender is in the perfect place and I could then have used a KTM inline thermostat unit which I already had. Sadly, I had already already fitted the head and the engine was in the bike, plus I didn't have the right tapered tap although I could have used an M10 tap and a reducer insert of course. But, take the engine out and whip of the head again... No thanks!

2, I could engineer an insert for the KTM thermostat unit that I could fit a temp sender into. It would have required a lot of work to do by hand and I debated if it would even seal properly. I could get it CNC'd, but that would make it expensive for a one off... I could have 100 made and sell them on... Not likely to be cost effective... Hmmm... Next!!!

3, I could do what the other guys do who fit these top ends, and buy an inline thermostat unit that does already have a hole for the temp sender already drilled and tapped into it... These units range from about $80 to almost $200, and they vary in size, shape, colour, material and also the temp of the thermostat mechanism, the size of the temp sender hole and also the quality...

So, since I didn't really want to whip my motor out again and drill the head, and I didn't want to mess with a KTM thermostat housing, I was left with option 3. I should have just got on with finding one ages ago instead of coming up with options 1 and 2 really.... Those other guys went that way for a reason...

I will freely admit I didn't do this lightly. In fact, I spent days trawling the net, looking at car, bike, ATV and Kart units, speaking to suppliers and putting sneaky low bids on ebay items...and... In the end I found the perfect unit to do what I needed at the best price was about 5km from my house! How bizarre is that!?

Ok, the unit by Kartelli is not quite the right size as it's not really short enough to fit above the head and below the rad inlet, but that is due in part as I had my Athena head welded with the 90Deg elbow and extension, luckily the unit does have very long ends, so I cut a little off the top and bottom to get the fit needed.

The unit has some really nice details, including the natty engraved ‘flow’ arrow, and the fact the stat is stainless steel, which the manufacturer found to have much greater longevity than the usual brass units found elsewhere when used for kart racing where they take a beating.

Pictured below with the KTM thermostat which is the perfect size, it just lacks the ability to incorporate a temp sender.

Temp senders.... I had a couple of rough looking units here and I wanted to get a new one, so I bought a bunch of those off ebay for a Land Rover which are the same unit I am told, and only 3quid a pop! Perfect!

The fittings needed work of course. I had a set off ebay that were designed for oil senders and so had a little hole and needed drilling out for the temp sender to fit through into the water. Simple to do with a drill if you have thin senders but the Land Rovers units are over 8mm thick so I had an idea to turn down the senders and found they are not that thick walled at 7(ish)mm... hmm... in the end i found a used LC sender with a 6mm end and used that. But interesting to know how far you can thin down a LR part if you ever needed to... LOL!

To be continued....

Athena bypass blocked up as not needed on an LC... I could perhaps have Tee'd it into the overflow, but that seemed counter intuitive so I just put a bolt in it and clipped it with clips so that I could easily bleed the air from cooling system when refilling.

I did think about using the Athena bypass in the head for the temp sender, but.... I didn’t want to pull it out and then try and re-tap it with the motor in place, and I’ve not seen the underside so don’t know what is under it. But might could be a good idea if you don’t use a remote filler cap, i.e. like the Banshee and RZs. Obviously I cannot use it as intended as the LC doesn’t use a bypass like this on its existing radiator.

I dont think you could mill more off the thermo unit than i have really. but i will be interested to see what you find. To be honest these things are pretty small really and it does fit fine where i have it, its not compromised any as the frame is in the way at that point so the hose steps it away from the rad etc. I could fit a 1cm longer lower hose if i wanted, I just chose to use an off cut, plus dont forget i have a welded up pipe on my head where pretty much everyone else uses a 90Deg pipe there, in which case you could run the thermo unit totally standard length wise.

The engine is the heart of any motorcycle and what began as a humble, yet also large,

stack of parts was combined to create something quite special to breathe life into this machine!

I found the Kartelli unit fitted nicely with the temp sender fitted instead of the blanking plug and also a few mm cut from each end, and I also dulled the sharp edges off the serrated hose ends as they were really very sharp.

I did this as I am fitting silicone hoses and they would have been cut by the sharpness of the unit instead of just grabbing nicely, which they would do with rubber hoses of course.

So far I have made use of the standard LC radiator. That might seem strange but it is actually a good starting point until I can source a well made, reasonably priced larger alloy unit, but to be honest I’m still not wholly concerned that many people would need a big rad, I guess it would depend on where you ride. In a cooler climate than Australia and being run on fast roads and no city I believe the standard Lc unit would probably suffice,a nd if not then just fit a fan from something like an R6. The reason I say this is that the standard RZ radiator is 450ml, the LC is 750ml. The upgraded RZ units are 750ml. Fitting the Athena kit to an RZ and you would default to one of the available upgraded alloy rads at 750ml, the same as the standard LC. Food for thought.

I firmly believe that I will need a bigger radiator as I am in a warm climate, I ride in the city with lots of stop start riding. I have dome some calculations and believe that 1000-1100ml is what I need. This with the impeller that ships water faster will work well as the greater volume should have a chance to cool the water before it flows back through the engine. When I spec this unit it will have a bypass on it as this will complete the system and allow easier air bleeding as it will occur naturally from the head.

In talking to my carb supplier I was been told that I would need to ditch the LC airbox as the carbs I am fitting to the 421 will need more air than that airbox can shift. Obviously really and I should have considered that before I started the build. Oopps. Naturally removing this unit is easier said than done once the motor is in the frame. hmm...

The LC airbox is in two parts and the top piece came off easily of course but I had to remove the inlet manifold to get the lower part out, easy enough to do, just fiddly and time consuming of course.

Now that things were getting finalised I fitted the vibration damping rubbers to the mounts and started looking at the wiring for the stator and the CDI/VDCI-04 combination. This was not expected to be a major task as the loom is new (albeit an aftermarket version with the cables at the rear is a a little short) but I found that the YPVS stator cable is too short compared to the LC version. Time for a think...

Ok, with a bit more searching I found the problem.... you'll laugh... or perhaps, look bemused, like I did...

If I had heeded the words of Sir Arthur Conan Doyle, as spoken by Sherlock Holmes, 'How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?', then perhaps I would have found this earlier... perhaps...

As no doubt all restorers of these engines would have done, I immediately suspected the shift shaft. They are known to wear and old ones always have groves or rust, or both... and new seals don’t like working with either.

But... there was oil on the mat again this morning, and it did seem an awful lot for a shift shaft leak. This led me to investigate further and of course I discovered that it wasnt the shaft at all.

well, see if you can see what's wrong with this picture?

Filters for these carbs in this frame are a challenge. Looking at filters that are out there and chatting to carious people it would appear that everyone struggles to find something that will flow enough air.

With some deft measuring it became obvious that I would need to run shortish cone, and even then I would need to bend them a bit round the frame rails as the mouths are pretty big.

One plus point of the LC is that the battery box isn’t part of the airbox like on the YPVS, so with the airbox removed its further out of they way than expected, but space is very tight in there with the shock and other parts...

I also sat down thinking long and hard at the stator. I did have an LC stator/rotor but it belonged to another engine which is in bits. I could borrow it and use it for a bit, but it will have to go back where it belongs at some point and if I’m honest i just feel the YPVS lump should really have the YPVS stator on it... Im not sure why? No one else seemed to have ever done this LC stator on YPVS motor backwards conversion when I asked, but going backwards in electrics on bikes is never something you would bother to try normally.

Whilst I have no filters and Australia is quite dusty I found that I had a bike with carbs waiting for me in the garage, and to tip the equation it’s a drizzly day so less dust... Amazingly quickly I fabricated a throttle cable and kicked the bike over... ‘Ring Ding Diiiing!... Bwahhhhh! ding ding...’ That old crazy frog ringtone has nothing on this thing, it sounds like a big MX’er!

Ok, I didn’t run it long... not only lack of filters, but the pipes are held on with twisted wire, and whilst the neighbours may not have been impressed, it was music to my ears!


Interestingly the LC stator has some adjustability in its slotted fittings so you can move it around which might be useful to some, but I would later find that it wasn’t enough for me when trying to setup up the static angle on the Zeeltronic. I will admit that I started off with a plan to fit an 83 YPVS stator, taking ages trying to fix the cabling, lengthening (the LC cable is long and the YPVS is much shorter) and then sorting out connectors (most were missing from the 83 stator I had) on a old 83 stator/rotor combo I acquired. But, it was taking ages, the cables were manky and old and I was losing the will to live... so, in the end I just fitted the LC unit which has good cables and is in nice condition. Obviously using the original parts means that the cabling is easier since it integrates with the loom easily, and I can always change it out later when I know the rest of the bike works. It only needed a new neutral wire (don’t they all?!) and it was good to go.

Next job was the fitting of the Zeeltronic VCDI-04 which is a piggy back to the CDI so the cabling is really very simple, it’s just 4 wires!

The LC stator is easier to integrate with the Zeel and the LC loom as mostly as the colours and functions are just a simple ‘clip together’, and the fact the LC stator only has one trigger wire, whereas the YPVS uses two.

The way it works is that the Zeeltronic receives the trigger from the stator and allows you to change it in the VCDI-04 unit before it sends it on down to the OEM CDI, which remains fitted.

So the connections are very easy; disconnect the trigger (white/red) from stator/cdi joint, connect one wire to each half of that connector where you took the trigger and add some switched power and earth the other wire. wow... Youre done! Compared to the huge bundle of wires on the Zeeltronic PCDI-10V for the YPVS this is a doddle! LOL

Found a switched power for the Zeel at the oil tank switch since I am not using the oil tank at the moment. A quick addition of a mini connector and I was sorted.

The pipes came back and went straight onto the bike and I rolled it out into the sun for a photo session, it looked how I expected and wanted. Good on both counts. So... I just needed carbs and it would run... 

The next task was to tidy up the last jobs on the exhaust pipes as they would be needed soon.

I welded on a second set of spring tabs onto the headers parts of the pipes. It’s not really that they need them as such as I’m sure they work fine with the single spring, but I wanted to make sure I had options when fitting the pipes.

I also ground down the last of the welds on the pipes with a Dremel so that they were ready for Ceramic coating, and have booked them in.

Plugged in the last of the other cables and added a battery, plugged in the Zeel controller and switched on... no smoke... phew! Neutral light comes on, Zeel controller starts up, tells me its a VCDI-04 and settles down to a 0 Revs screen. Horn switch works... Perfect first test!

Also added a quick connector for the trickle charger whilst I was at it... before buttoning up the battery side of things.

I decided I would run the ignition in the tail in the place where the tools normally live, more a factor of the length of the wires than any special placing tho. This also keeps it as far from the sparkplugs as possible which can be a source of interference for these units and we dont want any scrambled messages to the ignition at high revs!

I rested it on a foam pad and held it in place with an O'ring from a KTM oil change kit that was handily doing nothing on the bench... LOL

Everything had been going quite well for a while, so it was only to be expected that there would soon be some bad news on the horizon: On entering the garage I was met by a small puddle of oil under the bike. It seemed that the gearchange shaft seal is leaking. This is not uncommon when you reuse and old shaft that has worn a grove even when fitted with a new seal. I drained the oil and a new shift shaft (American for gearchange shaft!) was on it’s way from the USA....

As soon as it landed I fitted the new shift shaft and seal. This, as anyone who has had to do one will tell you, is a delightful job including removing the clutch to get to the shaft. I set about it with the approach of ‘Ahh well, if it’s done now it won’t leak for another 30 odd years...!’, and then refilled the oil and water and went to bed, praying not to see any droplets the next morning...

So... who wants a good news story about how fitting a new shift shaft and then carefully fitting a new seal using cling film over the shaft splines and lots of grease will fix my problem? yeah, me too... sigh, The bike is still dripping its lifeblood onto the garage floor, and if anything it’s now worse than it was before, I was confused...

One interesting thing about the new (Banshee, I would think) shift shafts, they don't have the indent for the gear selector running right round the shaft.

I think this is done to help idiots align the gear lever on a banshee, but its annoying when you have rearsets that need more adjustment. You can file it of course or grind it back with something like a Dremel, but its still annoying all the same. At least these new shafts are not expensive.

Keihin PJ34 carbs were chosen these should work well with this engine size for a street application, i.e. the power will not be 100% of what it might be with larger units, but it will also not drink a tank of fuel quite as fast either. They came jetted to suit, and my elevation and temps in Sydney are close on the same as LA, so they should be very close. With the carbs in place I could start to work out how to fit the cable and also measure up for filters. The engine would soon be a runner...!

I had never noticed it was missing and to be honest I didn't even know they were removable... Luckily I had another engine I could borrow one out of it for now.

As these plugs are not designed to come out, you need to remove the transmission shafts and then knock them through, it took more force that I expected and I can only assume the one missing from my engine did not fall out, so a previous owner must have needed it for something, the mind boggles!

The good news is that this fixed the leak (obviously) and I did’nt need a new shift shaft, which is nice to know, I guess...



I spent a long time online looking at filters and settled on K&N R-1260 units. The K&Ns are recommended and tuneable, unlike some pod filters.

To prove they would fit in true Blue Peter fashion I thought I should make some to test the fit... they just go in and will need a little bend in them for the chassis rails. I discovered that had I been able to locate an angled flange version of around 10 degrees that would have been better, but these do fit quite well enough.

I also cleaned up the wheels and re-polished them and did the same to the pipes when I put them back on, with the o-rings this time and the correct rear bracket fittings. Nice snug fit on the with the o-rings and I'm happy with the fit. There is obviously too much oil tho, the pipes stink of oil and the ends are wet. Time to mix some bespoke fuel and go with that.

The airfilters arrived and were bolted on. As they are cones they fitted in ok as per my mock ups. The back of the filters is smaller than the front so they sit either side of the rear shock with no problem. The back of the filter on the battery side needed a bit of manipulation to fit as the battery box edge is in the way. You could easily cut that corner off the battery box though if you have a shorter battery. The front of the filters hit the frame on both side where the frame rises from the foot rests and starts to bow inwards towards the spine at the top. At that point I just pressed my thumbs into the filter's steel gauze and dented them a little and now they clear the frame with no problem at all. As this is the filters’ widest point and its beyond the side of the mouth of the carb I figured it wasn’t going to be too much of a performance problem.

For anyone following this and doing their own build, this might be different if you have a different inlet manifold. If you recall mine is the Wicked internal crossover unit and I have Vforce 3s matched to it. That manifold lifts the carbs up a little and is a little longer than the OEM types. Im running PJ34s as well, so different carbs will make a difference to the fit as well.

At this point I also fitted the 45 degree carb tops I had from Allens to these carbs and adjusted them so that they close fully, but they do struggle to get enough lift from the standard YPVS throttle cable and Im a few mm off the top at full gas. I was a bit perplexed by this as there must be an issue somewhere as the standard LC throttle cable I used when I first rigged up the carbs had further travel. Investigations found that the lower throttle cable parts (i.e. below the splitter, to the carbs) are fine, its just the top bit from the splitter to the throttle that seems like its not moving far enough... hmm...

I had a lot of fun and games with setting up the initial ignition timing. This was for two reasons, one that I had the LC stator in the YPVS engine, and two, because I was using a Zeeltronic and so needed to set it so that I had as much advance as possible in the system in case I wanted to use it.

The following is how I eventually managed to set up the

base static angle setting:

2, Adjust the Zeeltronic for a constant 20 degree advance.

This is completed very easily done on the Zeeltronic as you just make a (straight) curve with say 4 points of 20degrees as one of the programs. These VCDI-04 Zeeltronic units have 10 programs so using one for this is simple.

Picture shows the Zeeltronic with the bike running.

3, Use a timing light to see the 20 degree mark and check.

Set the timing light to zero, so its not adding any delay, also set it to 2 stroke and on timing degrees and strobe, not on tacho...

4, Set static angle on Zeeltronic  to align the marks.

5, Then increase revs to see that the marks stay put, if not, then there is a compensation adjust to correct any dynamic error.

5, Then increase revs to see that the marks stay put, if not, then there is a compensation adjust to correct any dynamic error.

Interesting note: One of the many things that I did learn from this (very long) exercise to sort out this static angle is that the the Ignition reads off the leading edge of the trigger (on the rotor) and the sensor (on the stator).

In the end I found that I had to slot the LC stator on the clockwise side to get 27deg advance, I only managed to slot it 4mm, which was not as much as I would have liked, as the YPVS is usually set to 36ish, but thats all I could get from it due to the bolt placing, even with allen headed bolts!

1, set up at TDC.

Initially I did try 20deg BTDC and I used a dial gauge down the plug hole. It was in inches which was annoying but 2.177mm (due to my +4mm crank, 58mm stroke and 115mm rods) is 0.00857inches and that wasn’t too hard to work out on the gauge actually. So, setting to zero or TDC is simpler really...!

Picture shows my ‘T’ (for TDC) mark and my other lighter mark at 20deg worked out with the dial gauge when lit by the strobe.

One thing I did notice when doing this work was that with the rotor off I could see some bizarre pitting on the inside of the rotor and the converse was that material appeared to be being added to the crank taper. It was there in three different points and looked like it might be 'weld' from a bad earth thats arc'ing between the crank and the rotor. Bear in mind this was a new crank, so it was unmarked when fitted.

I used valve grinding paste and lapped these parts together to get these parts to fit nicely, this was easily done with freely available coarse and fine pastes from a motor factor, lifting to redistribute the paste as I went along. The result was a nice wide band of grey where the parts met. perfect.

A friend and I were chatting about this work and he said something that set us both thinking... if you measure TDC and/or the 20deg point, ie 2.177mm for me, on the rotor against the obvious mark supplied by the timing tell tale then if you move the stator then you need to re-measure and re-mark those marks.... but if you mark the rotor relative to a dot you make on the crankcase, then you don’t need to keep re-testing and re-marking as when the stator moves it doesn’t matter for the marks as the marks are in the same place on the rotor every time as the rotor is fixed to the crank, which is fixed to the conrod, which is fixed to the piston (arm bone connected to the... etc)... it’s the stator that's variable and being moved... so... perhaps to save time when doing this setup, just measure the TDC / 20deg marks once against something that doesn’t move, i.e. a dot/mark on the (also non moving) case.

Also... we agreed that for those who struggle to find the TDC due to the float, that you may not wish to measure and mark TDC... whilst that’s a great and simple thing to do for other, and of course with an adjustable timing gun you can play with that, but... that little float at TDC can mess up your figures if you’re not proficient in measuring it. So... we agreed that you could actually use the dial gauge and measure back to BTDC the right amount. If you do that the float is eliminated as the gauge will either move or not, there is no messing about trying to feel the TDC. Experts who can happily find TDC should do that of course...

Many forumers have been impressed by the service offered by Arrow I was more than a bit interested when Gary said he was going to create an uprated +18% autolube pump for bikes with 68mm cylinder.

After he and I chatted for a while about premix and pumps in general he quickly convinced me that he knew what he was doing and I should find a pump and get it up to him for modification.

I found a pump (see pic on the right) on Norbo’s forum and had it sent to him was more than a bit blown away by what landed in the post when Gary was done.

Talk about a clean and new part... the pump is a thing of beauty, not the lump of junk I sent him.

My advice, send your pump off to Arrow - you know it makes sense...

Talk about a clean and new part... the pump is a thing of beauty, not the lump of junk I sent him.

My advice, send your pump off to Arrow - you know it makes sense...

The extra yellow paint is to say "350+18%".

I just need to locate the rest of the parts and I will get this fitted... So...

"I love it when a plan comes together!" Is what I would have said if only it had... Fans of Hannibal, the Salt n pepper haired A-team leader*, will remember that after a bit of backwoods engineering the team could get out of any impossible situation and part way through the subsequent action, when its was obvious they were winning, he would utter that immortal line... But, back in my garage, my plan wasn't coming together at all...

* - Amusingly I always thought of Hannibal as a really old guy who was pretty sprightly on his feet, bizarrely I checked him out and he was 46 when they made the first A team episodes. Ooops, maybe he wasn't old at all.... :D

My plan was to start doing the list of jobs to complete and tune this bike. I've been gathering parts for a while, but first up I wanted to fit a +4 degree key to the crank to get a few more degrees of static timing and then redo the static timing and re-apply the curve. Of course, I could have just left well alone, an extra few degrees wouldn't be the end of the world, or I could have just changed to a YPVS stator and rotor; but since my bike works well with the LC setup (and it was easy to wire with the LC loom) I decided to stay with it and for an extra few bucks why not get the advance you can in case you ever need it.

First job was to remove the gearchange so I could remove the left hand engine cover. Usually simple, but I had fitted a domed stainless socket head bolt to the gear linkage where it joins the shift shaft and I didn't get the allen key in properly and rounded out the fixing totally after a few tries. Damn! With nothing to grip due to the dome, I had to Dremel a slot and use an impact driver with a large bit to get enough purchase to turn the screw, no hitting was needed luckily, just the might of the way an impact driver seems to lock up nicely, as I didn't want to bend the shaft. Moral of the story, always fit a normal headed bolt to these parts.

With the cover off I could remove the flywheel. And while the nut came off easily enough the flywheel resisted all my attempts to mate it with my flywheel removal tool. I remember this flywheel was not happy with the tool last time, and since then the tool has gained a few battle scars, but wow it just wouldn't thread in at all this time! A lot of messing with files, brushes and picks in the threads of both parts and finally I got the flywheel off. But what a nightmare. Afterwards I spent a bit more time making sure the flywheel and the tool like eachother better on the bench, but they are not a very nice fit for some reason.

Finally after hours of work I could do what I set out to do... fit the +4 key.

The +4 key doesn’t look much, but of course a small amount of distance close to the center of the crank goes a long way in degrees.

With a bit of fiddling I got it in and the flywheel went back onto the crank and I whipped out my new tool that uses a spark plug threaded insert to mount a nice new metric dial gauge to check for TDC and then measure back to get a 20deg mark for setting up my new static angle. You could quite easily see from the old and new marks that the +4key was doing its job and was the right way round!

Next on the list of things to was was something kind of sexy! I cleaned up and painted my recently acquired LC left (flywheel side) engine cover. I originally had a cut down (not by me) RZ case side on there, but I didn't like the cut down look so wanted to go OEM on that cover. I found a half decent one on ebay but even that turned out to be scratched under its 2 layers of paint, but at least not a bad road rash scuff like most you see these days. Anyway, perhaps not an earth shattering event to many but the right unit is now fitted and looks much better as it fills the frame rails properly now. One thing that is interesting about these covers is that they are alloy and have an extra shift shaft bearing in them, they even have a seal on that part... which sort of seems overkill, but its a nice touch.

Next I hunted down something that's been bugging me for ages. I have my Zeel VCDI-04 in the tail of my bike. I’ve been securing it on a foam pad using an o ring wrapped around the strap holders that secure the tool bag in place. Every now and then I notice that the cheapo (ALDI) o-ring has perished again and remember that I really need to find a better solution. I was idly thinking about this today and remembered that about 6 months back I picked up a box of old parts from a friend locally who wanted rid of it to a good home. Most of it was scrap but there were some useful things in there including a short yamaha strap. I finally remembered to look it out and see if it fitted... it’s like it was made for that job! Perfect!

One thing about spending years working on the radiator for your bike is that you know all sorts of facts and things that will never get you laid... ever! Try this: The RZ rad has a tiny sub 500ml capacity and the LC rad at 750ml, just like a bottle of wine... and is the same size as the high flow RZ rads you can buy now... Useful facts for sure, but ya see what I mean? ...Yeah...

Anyway, because of this I decide usually to keep my excitement about radiators to myself, but while at Wicked in LA Roger showed me the Aprilia project he had been working on and in the discussion I picked up a hint about what might be the radiator fix for the 421. As regular readers and visitors to my garage may know, I’ve struggled to find a rad that would work for this bike.

Those that have tried have found that cooling is interesting on these bikes, not just cos the 421 is a bit bigger than the original 350, after all it puts out a bit more power, but replacing the spindly LC forks with the RGV USDs and the fat front wheel/tyre and front guard mean that most of the air is punted everywhere except thru the radiator, not at all ideal in Australia where we have quite high summer temps. This means the bike runs warm always, even with a high flow impeller (it just pushes the water wound faster and since its not being cooled...), and in traffic it gets positively hot and so needed a real fix.

While I know a few guys with big bores bought high flow radiators from ebay and other sellers, my issues with those units was usually two fold, either they were expensive (although beautifully made) or not wide enough, I say that as Oiler (Brian in Aus) had to invest heavily in a huge alloy scoop to pull enough airflow from around the sides of the front end. Very mad max, but I was hoping not to spend quite that amount of course...

This left me with an ongoing (last 3 years!) project with local guy Pete (DOC03), who had an R6/RZ 421 project, to create a wide rad that would fit both my LC and his RZ frame. We designed it, made mock ups from beer boxes and did usable technical drawings, but with his eventual selling of his project that all came to an end and I was left with my 421’s cooling on the back burner indefinitely...

For info the rad that Pete and I designed was planned to bring up the capacity of the unit to between 1.1-1.2L, sit 10cm wider than the standard LC unit, be 2 rows and have wider core passages. The plan was that with more coolant and width we would catch air to cool more of the coolant on each pass and as we used thermostats and a backup R6 fan we would hopefully be covered in traffic as well as the open road. We had the option to use high flow impellers or not, depending on if the bike ran cool or not and temp controllers to switch the fans in when stationary.

All that fine tuning trickery aside, the biggest problem with designing your own rad is that of getting it built. Shops like PWR will love you and then quote ‘about $800’ to do this work... Ouch! The Chinese, who do some good work (when they want), have no concept of design work, they only copy. Im not joking. We even asked a few of the sellers to literally “make me the LC rad you do now, but with a 10cm wider core” and they replied ‘send me an example and we will copy it’, and no... they didn’t want to use a drawing. Hmm...

So, it was fortuitous that when talking to Roger I noticed the rad on the Aprilia, one that he found as he actually had the original machine in the shop at the time he needed a solution so was able to take measurements. I took note of it and did some research when I got home and ordered this:

With the rad bolted on:

The units dimensions are bizarrely almost a perfect fit for the base rad that Pete and I designed after a lot of research and discussion. The core, the outside measurements and the capacity are close on what we had in those plans. Amazing.

In fact my googling turned up that we weren’t alone in using this unit, the Kawasaki 2T boys had been using them for a few years.

Ok, so no, it's not perfect. I would have preferred the tanks on the top and bottom not the sides, and it still needs brackets, new hoses etc etc... but it was only $84 shipped. Cant argue with the value!

I spent some time fabbing up a bracket setup and some more time spent adding the R6 fan to the new bracket but when trying it for dimensions on the bike its was not what Id call perfect. oops.

It could really do with being higher to catch more air through the forks, but that brought its own issues with the top hose and the fan...

TiMe To KoMpRoMiZe

Sigh... Yeah... I know... No matter how you try to dress it up and make it look cool, it still sucks.... Big rads in small bikes... You get me?

So, I’ve been working on the bracket for the rad Mk2. There has been a lot of head scratching and deliberation, but here is the unveiling!

For those who want to do something similar, the problems you need to get round with this are:

- It needs to sit high up to be above the wheel/guard and catch the air between the forks

- The LC is very tight on the frame rails, it narrows more than the YPVS models.

- The LC has a bar right where I wanted to put the fan... oh yeah, didn’t I mention Im also fitting an R6 fan, you need to step out the rad for that.

- The inlet and outlets need to work for the engine connections to keep the same flow

- The steering, forks and brake parts cant hit the rad when turning the bars if its too high/far forwards

- The wheel/guard cant hit the rad on compression (and turn) under braking

Phew... Just a few  KoNsTrAiNtZ  (see what I did there? hmmm)....

So I couldn’t put the rad quite as high up as id have liked, but I did get it pretty high up on the frame, this now also looks right in silhouette which means its in the right place, Ive found that if the proportions look good and the location looks right, it often is.

Next on the list for the rad is fitting the AMD (its an old IBM in joke for those reading this who’ve ever worked there) controller.

The bracket with the fan fitted:

I’ve always wanted to find and fit an RD/RZ500 kickstarter. I know it’s crazy but I reckon they look the best of the aftermarket units and of course we all know they are light, strong and decent quality, which is sadly not always an accusation you can lobby at all of the aftermarket units. But everyone seems to want one and now they command strong money where I am and post always seems to kill the deal from overseas. I was idly perusing ebay and found a local breaker had one in stock, it looked a bit scabby and wasn’t cheap but a couple of emails later and it was mine for a bit better than the ebay price, phew!

First question was how to modify it to fit the 250/350 application... Reading around on the net, it appeared that there were three schools of thought; Modify the 500s body to fit the original 250/350 knuckle or modify a 2/350 knuckle to fit the 500 starter arm, or use the original 500 arm and knuckle.

Option 1 is pretty easy, you just cut/file down the body of the starter arm. I didn’t want to go this way as being alloy I think you want a bit of strength at this point, its where the cranking occurs and there is quite a bit of force across this areas. And why modify (and potentially ruin) an expensive part if you don’t have to...

Option 2, Requires you to extend the 250/350 pivot at the knuckle to accommodate the extra height of the 500 kicker. This can be done in a number of ways, either by welding on the 500 pivot, extending the old pivot or drill and tap the pivot to accept a bolt to hold the 500 arm on.

Option 3, In order to keep the original 500 knuckle you need to drill and tap the 250/350 kickstart shaft to accept a bolt. This is close to the OEM fitment for the 500 kicker which uses a big washer and nut to keep the kickstart on the splines, not a clamp like the smaller bikes. But the mods don’t stop there as you also have a small problem in that the 500 unit also turns within its own setup, and needs a dab of weld on the two parts of the knuckle to counter that.

In the end I decided to go with a two phase approach based on option 2 and drill, tap and fit a spacer with a bolt in the top of the 250/350 knuckle. The 250/350 part is actually only about 6mm shorter than the top edge of the 500 kicker as in use it sits about 5mm above the 250/350 arm to allow for the OEM washer and clip fixing, this means the majority of the 250/350 pivot arm is in use when fitting the 500 unit, this got me thinking about the mechanical strength of the joint and how much force would be exerted on the fixing for the kicker. I believe the fixing I’ve created will be strong enough, but if it isn’t I could later either extend the pivot pin with weld or fit the 500 knuckle, we’ll see, so far Ive only ‘ruined’ a 250/350 part which I had spare anyway.

I used a KTM 620SC OEM alloy exhaust mounting washer, its the perfect size to match the width of the starter arm body as well as the OD of the pivot is the same as the ID of the body, plus it is thick and strong yet light weight. I’ve fitted a lock washer between it and the pivot pin to give some movement and help lock it in place, with a nylon washer between the big washer and the kicker body to allow decent rotating movement. The 500s ball bearing fits the 250/350 knuckle so that part you get for free, tho you do need the 500s lower plate if you don’t modify the divot on the 250/350 knuckle. I didn’t modify that, but could have done, its originally steel to protect the alloy kicker from wear so I kept that feature in my setup. Leaving it out would gain you 2mm of height on the knuckle and mean more of the pivot was inside the the kicker arm, adding strength.

I blasted the grubby and nastily painted/chipped 500 kicker with glass bead after tidying up the casting a little. Serviced the ball bearing parts and blasted/painted the OEM 500 lower spacer plate. Once dry I assembled it on the bike with loctite, while ensuring the action felt smooth yet firm.

Looks good and feel strong, lets see what its like in use I guess...One of the things I really like is how neat the 500 kicker is when not in use, its got a subtle bend in it to keep it closer to the bodywork than the OEM 4L0 or 29L units

With this bike coming apart for a new frame there were a few engine related things to do, not least fit the EGTs and the oil pump. Firstly I made up a pressure testing kit for testing this motor before it went away for storage as Id never done it. Yes I know... I know...

And... Lucky I did as there was a hole in the rubber flange that the carb bolts to! OMFG!

Looking at it I can see that the jubilee clamp was badly pressed together during manufacture and there are some metal pieces that should hold the bolt captive, yet on mine they'd bent and moved inwards and went right through the rubber causing a 2mm hole!

Testing would have to wait until the new one is fitted and the clutch cover was off for the new +18% oil pump, that way I could access the crank seals and check they and the primary drive gears weren’t leaking any air.