Cycle News - Archive Issues - 2000's

I markets - somewhat inevitably, the non-PC V-four two-stroke was never officially marketed in the USA alongside a total of 3700 aluminumchassied versions producing around 10 hp less, built exclusively for the Japanese home market under the RZV500R tag and representing Yamaha's first volume production model with an alloy frame. "I'd been biking since my mid-20s, but when I got posted to Okinawa I sold my 900 Ninja because I knew I was going to buy a two-stroke Yamaha soon as I got there," states Belorusky with a glint in his eye. "It's a dare-to-be-different bike that even back then you never saw on every street corner. And being 6'3" tall and weighing 240 pounds, I was automatically disqualified from riding a 250 or 350, so it had to be the V-four." Back home in 1994, Wyn set about correcting the constraints of Yamaha's accountants by concocting the ultimate GP racer-with-lights, using one of his RZV500R Yamahas as a basis, aiming to create the closest thing to a naughty- '90s 500cc GP bike you'll ever see on the street, with the aid of his friend Steve Cisewski. "I can come up with the ideas, and machine and fabricate the components - but I can't weld," says Wyn. "Steve glues the parts I make together - we make a good team." The first objective was to stiffen the stock chassis to handle more power and extra suspension loads, as well as to achieve the Deltabox GP look that was Wyn's objective. This meant adding an extra aluminum box section frame spar under the original one to double up on depth, milled and welded to look as if born that way and coated with high-impact black paint. The steering head and rear-engine mounts have all been reinforced, the rear subframe is now detachable, and the frame cleaned up with the removal of unnecessary tabs, then fitted with a swingarm from a '94 Suzuki GSX-R750 modified to operate the Ohlins rear shock Wyn had sourced (shortened 20mm to retain the original 1375mm wheelbase and 'banana-ized' to allow both exhausts from the lower pair of cylinders to exit side by side on the right, just like on a real GP bike). A '96-model GSX-R750 donated the upSide-down forks, fitted to billetaluminum triple clamps machined from solid by Wyn himself and fitted with a titanium stem, but maintaining the original RZV500 steering geometry. To replace the original skinny 16inch front/18-inch rear period wheels, Belorusky sourced a pair of current 17-inch Marchesinis - the rear a much fatter six-incher - fitted with D207 Dunlop rubber and running on titanium axles from New Jerseybased Yoyodyne, who also supplied the 190mm titanium rear-brake disc. The front brakes are British-made PFM cast-iron discs gripped by the '96 GSX-R750's six-piston Tokico calipers (rear is a Brembo sourced from a scooter found in the Okinawa wrecker's yard), while the bike is littered with numerous examples of Wyn's fabrication expertise and attention to detail, like the carbon-fiber rearset hangers, rear-brake lever and dashboard, plus titanium footrests and The Yamaha RSVSOOR and its SOOcc V-four two-stroke engine is licensed for street use - well, at least in Florida it is. crankshaft 50-degree V-four's cylinders -which stiU retain the stock YPVS power-valve system - reshaping the heads and recutting the squish bands, retiming the stock ignition, then fitting a quartet of 28mm Mikuni f1atslides surmounted by K&N filters to feed the engine via RZ350LC reed cages modified by Kevin Cameron and fitted with TOR reeds. A set of race-type expansion chambers are fitted, two each by rival exhaust specialists Harry Barlow (uppers) and Brian Turfrey (lowers), but with the four silencers and billet alloy flange mounts all Wyn's own work. Okay, so it was time for me to seek out a quiet stretch of Central Florida highway, even one with a few turns, and get a feel for the first twostroke streetbike I've ridden for a couple of years, ever since the famously flawed, fuel-injected Bimota 500 V due of recent memory. Except, the ring-ding Belorusky bombshell preceded that in concept by more than a decade, and in completed form by a couple of years. So how does the one Wyn did earlier stack up against its Italian rival? Well, for someone fortunate to have track-tested a fleet of mid- '80s factory GP racers, riding Wyn Belorusky's RZV500R represents both a trip down memory lane, and a what-if window on the sportbike twostroke world of today. What's most noteworthy, and surprising, is that Wyn's Weapon should be so wellmannered, usable even, at road-legal speeds - and remember that in the USA, that means 35 mph in lots of places and a top limit of 75 mph on freeways and four-lane highways. Perhaps because of that, Wyn has geared the bike down quite a way, so that the 11,500 rpm mark at which the estimated 100 hp is delivered he's never put the bike on a dyno, but that seems realistic from riding the result - delivers around 130 mph in top gear before the power tails off as it's presently geared with four extra teeth on the back, whereas 155 mph with stock gearing would seem to be a reasonable expectation with that increased power delivery and above all the slash in weight. If only you could find somewhere outside the reach of the Florida State Troopers to test that presumption. But it's confirmed by the Avocet 45 bicycle speedometer improbably mounted to the dash (complete with carefully fashioned external reading lamp must be able to see it at night to get that Florida license tag), which registered 107 mph when the racestyle '80s analog tach measured aluminum gearshift pedal, assorted spacers, rear-brake torque arm and clutch and brake hand levers all machined from solid, and matched by a TZR250 switch gear and throttle assembly. The completed bike is clothed in a set of carbon-fiber bodywork sourced from the Team Roberts mould for Wayne Rainey's '91 YZR500 works Vfour, fitted with a pair of 55-watt headlights that are in fact foglamps developed for a Low Rider four-wheel custom cruiser such as is all the rage in South Florida these days, and matched by a carbon fiber fuel tank with an integral oil tank for the Posilube separate oiling system. liberal use of exotic materials and a ruthless approach to removing unnecessary metal has enabled Belorusky to slash the dry weight of the complete bike to just 295 pounds, compared to the original stock RZV500's 395-pound mark. "I figure there's 100 pounds of motorcycle somewhere in my trash can," states Wyn laconically. To deliver power to match, Belorusky enlisted the help of engine tuner B.J. MacDonald to bump the stock j-model RZV500's power output up from 68 hp at the rear wheel to something over 100 hp in its current guise This involved porting the twin- Cathcart finds one of the few corners in Florida to test the handling of the V-four. ... u ... I e n e _ s • JANUARY 23. 2002 21

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