special brews YOUR BIKES, YOUR WAY
Standard Yamaha RD350YPVS or RZ/YPVS hybrid? Can a homebrewed mongrel top the factory product? Let’s see
Everything comes back to two-strokes in the end. No matter how far we think we’ve come – we all end up back at the start point – with strokers.
Huge progress has been made with fourstroke engines, but despite massive power outputs and numbing reliability they remain poor relations to the two-bangers when it comes to cheap thrills (and not quite so cheap these days, either).
A 1970s or 1980s four-stroke is a deadly dull thing to ride compared to any stroker of similar capacity. Would you have preferred an GT250 Suzuki or a CB250 Honda in the 1970s? Precisely. A 250/350LC Yam or a Kawasaki GPz305 in the 1980s? No further questions. Case dismissed.
These days you don’t have much of a choice – it’s four-bangers for all. Unless you’re prepared to take the leap back into the heyday of the *Day-cycle engine and snag yourself a late-’80s/early-’90s smoker.
Mark Hynes (pictured, left), fettler of the YPVS, and builder of the RZ/YPVS hybrid on these pages laments this situation. “It’s all very well not losing money on bikes, but you’d much prefer some younger riders got the chance to ride these old two-strokes,” he says. At 53, he actually is a younger rider. But let’s ignore the demographic and examine the machines.
In the common parlance of eBay (not that these bikes are for sale) here we have… a 1983 Yamaha RD350LC YPVS, UK-bike, hardly messed with aside from original (Codnor Light Fabrications) Micron expansion chambers. Here, we also have, a 1984 Yamaha RZ/YPVS hybrid with 1983 Yam YZF125R running gear and a 350 Valve engine on Alonze spannies (with Arrow stickers on the mufflers). I don’t know where people stand on silencers/mufflers these days (or even back in those days), but strictly a silencer should, like, you know, silence a noise. A muffler, like, you know, muffles it. The Americans prefer it, and in this case they’re right. So muffler it has to be.
We could bind on forever about what Mark did to these bikes, how he did it, when he did it, but it’s only relevant to the mutoid RZVS.
The largely standard Valve is simply an exemplar of the first 31K model – so utterly period – even down to the woolly carburation from 5500 to 6500rpm courtesy of the Microns. Factor in poor braking from twin discs, still astonishing levels of comfort (for what was a 100% sportsbike of its time), six-spoke wheels with those magical circular cutouts, all in that impossibly seductive pearlescent white base, and you have an historic YPVS of the greatest allure.
