Taken to the Max - Yamaha RD/YZR

When Peter Kent decided to build a Biaggi YZR replica he was never going to hold back on authenticity – only on money

 

All it took for this remarkable build to reach rapid fruition was one photograph. One solitary picture of a factory Yamaha YZR500, and Peter Kent then took just one year to make this Moto2-framed RD500LC a ring-a-ding reality.

He was clearly the man for the job. The 59-year-old nuclear planning engineer is no stranger to working in the critical application arena. Plus he had the added advantage of working as a mechanic with the British two-stroke race engineers Barton Phoenix for a year in 1978. Based in the Nazareth Chapel in Caernarfon, Wales (as if Caernarfon was ever going to sound like it was anywhere else), Barry Hart and Graham Dyson were at the core of two-stroke development work in the late 1970s.

“I learnt so much there,” says Peter. “Barry was savvy. He used tried and tested components. There was no need to reinvent the wheel. It was TZ750 bits mainly, someone’s done the hard work making these parts perform – use them. And that’s my theory too.”

So, with Moto2’s second frame off the jig in his hands after an American customer’s order became available, Felix at the York firm CAD-programmed it into the form you see now; ready for a very stock but painstakingly assembled RZV500 V4 engine.

“I’ve got a mate who does vapour-blasting and that’s where I saw the engine and that was when the build started gathering momentum. We replaced everything, but modified things to keep the engine cool and let it breathe.”

 

"Kept standard you'll get some life from from the engine. Don't forget this is tax and tested. I have to go down the pub on it."

 

500LCs can cook their rear cylinders if they’re not cooled effectively. Airlocks in the system are the killer. Peter used an R6 rad, just as the same model was the donor bike for the front and rear ends, but he made sure it was plumbed in to let cooling air circulate around the entire engine – not just be fed into a tight aperture for the rad alone.

“We pushed the fairing out by an inch either side, not only to get more air to the stock carbs, but to give the engine a chance to shed heat. I’ve got an MV F4 too. That overheats like nobody’s business given a chance – solution – take the fairing off. Keep things as exposed as you can.

“It’s got the standard Mikunis on it and I designed air filters that would fit within the YZR fairing. Two plates sandwich 30mm of foam with reliefs for the venturis. I’m looking for reliability not outright power. If you leave it standard you’ll actually get some life from it. Don’t forget this is a taxed and tested machine. I go down the pub on it.”

It takes to tracks too – like a duck to water. It’s been to Tonfanau (Wales again), done parades at Silverstone, and Prescott Hill Climb too. “The only real problem when we shook it down at Tonfanau was fuel starvation. It worked beautifully at halfthrottle but emptied the float bowls at wider openings. The NC30 tank had the one tap and was never enough, but after I fitted twin 8mm taps it was fine. The throttle cable routings were an issue too, but all in all it was good straight out of the box.” Note the use of the phrase “Out of the box.”

Fact is it came straight out of Peter’s house. “I like two-strokes, but I don’t like buying them, I much prefer to build things.”

So, his conservatory became the workshop for this creation. “I’m quite lucky because my partner Jill works in Zürich and I only work a three day week. There’s nobody here to give me any grief, no one to police me. I only have to tidy up for one long weekend a month.

“Once I start something I just try and get it done. I’m not OCD or anything, but I’m a job planner. I break a task down into hundreds of parts and then tick them off. That gets it done. If a bike takes four years to build, then the way I look at it, that’s four years you’ve lost riding it. It makes me giggle because if you just gather up the right components YOU can do it. The only thing that had to be made was the frame.”

Tidy double LED installation

Tidy double LED installation

Yet every disparate component has to fit. And fit perfectly. Peter has a lathe and a mill at home. Not in the conservatory, but on the premises. All the brackets, spacers and mounting plates are his, all the swarf swept away for that one long weekend when everything has to be shipshape.

Because he sourced his donor components cheaply (mostly R6) and because he could do much of the machining and all the assembly himself, this was a staggeringly cheap build – for this standard of the bike. Try £12,500 all up. Jeez, there’s some truly duff stuff around, some real dog’s dinners that are double that.

“I’m not sure I could do it again for that money,” he sighs. “RD bits are way on the up now, and there’s four of everything don’t forget. You go to Padgetts for TZ stuff and Clive will say, ‘Come and sit down,’ before he gives you a price. But it’s important to build good replicas because soon we won’t see the real thing because of collectors and because of how much money the genuine machines are now worth. You can still see these now and if you’ve not seen them first time round how do you know they’re not real?”

It’s a decent point and one that the many admirers of not only this RD/YZR but the Mk1 RG and Schwantz replicas Peter’s built too. It’s good that Max Biaggi’s tweeted how good it was, Niall Mackenzie too paid me a huge compliment. He said (and I think I understood him), “There’s lots of people build these bikes – but you’ve actually got it right.” Mackenzie got that spot-on. Pretty as a picture, and no mistake.

 

BODYWORK

“Everyone loves a Yamaha V4,” says Peter. “But not everyone’s a Max Biaggi fan. Jim Lomas’ stuff is top quality and the only issue we had was painting it. I wanted a black pinstripe separating the red and white. Painter Ryan kept saying ‘No way’. And of course he was right in the end.

FRAME

Based precisely on ROC-Yamaha geometry, Blue Haze’s YZR replica is an entirely faithful YZR copy. “How do you know it’s not real?” says Peter. “You’d have to be some rider to tell. You can get the power on so early out of turns with this and it just keeps driving. It’s so easy to ride.”
 

PARTS

“I kept it all local to the west coast, and bought parts off the internet. You can pay £800 for a replica alloy tank for example, but a Honda NC30 one looks almost exactly the same and will cost £80. Things like brakes have to be the real thing, but you don’t need magnesium wheels.”
 


ENGINE

“Keep it standard and replace everything, paying special attention to cooling,” says Peter. “Cable routing is also critical. The clutch cable has to go through the frame, and be prepared to keep rerouting things until they’re right. Every time you go near it be prepared for another refab job.”

 

 

SPECIFICATION

Yamaha RD/YZR

ENGINE standard 499cc, liquid-cooled V4 built by Alan Tinnian, 26mm Mikunis, Zeeltronic digital ignition, Yamaha R6 radiator, pipes by Barry Dawson at Blue Haze, air filters by owner Peter Kent.

CHASSIS Moto2 YZR replica by Blue Haze, Yamaha R6 forks, swingarm and wheels Brembo monobloc front calipers, Brembo P83 rear, Honda NC30 tank, YZR bodywork by Jim Lomas, paint by Ryan at Fat Badger Race Paints, all spacers and brackets by Peter Kent.