Source: Bike Bound
[[{“value”:”350-lb, 100+hp RZV500R from Championship Cycles…
In 1984, Yamaha unveiled the world’s first two-stroke V4 production motorcycle, the RD500LC — a 500cc road-going replica of the YZR500 that King Kenny Roberts rode to the 1983 GP World Championship. Known as the RZ500 in Canada and Australia, the V4 smoker showcased some truly exotic engineering for the era: Yamaha’s YPVS servo-controlled power valve system, horizontally-positioned rear suspension mounted beneath the engine, and different induction systems for the front and rear banks of cylinders (crankcase reed valves in front and piston reed valves in the rear).
“The RZ500 was a dream-come-true for race enthusiasts worldwide, and naturally, it became a highly lusted-after machine.” -Tom Fortune, RZ/RD500 Owners Group
King Kenny on his YZR500. Photo: Henk Teerink
However, the Japanese domestic market (JDM) received an even rarer and more exotic version, the RZV500R, which boasted a hand-welded aluminum chassis to save weight. While the RZV weighed 20 pounds less than the steel-framed RD/RZ, the engine was detuned from 88 to 64 horsepower to comply with Japanese legislation. Of course, unleashing the 500cc V4’s full power potential inside this lightweight chassis would be the ultimate fusion…
Enter Mike Vienne of Championship Cycles — a man who focuses on transforming production sport bikes into machines that better reflect their race-bred counterparts. The shop takes the words of Colin Chapman to heart: “Simplify and add lightness.”
“Championship Cycles began from the idea that less is more — because more is heavy and heavy is slow.”
The bike you see here began with a rough but running JDM-spec ’85 RZV500R. The owner originally wanted a Wayne Rainey Marlboro replica, but as that’s been done before, Mike had other ideas:
“I proposed an alternative design — one that recalled the GP motorcycles that ran the Daytona 200 in the early 1980s.”
Mike gives us the full story and specs of this “RZ500RR” special below. Here are a few of the highlights to whet your appetite: engine rebuilt to 100+ hp spec by Wilson Performance, race-cut transmission, four titanium chambers designed by pipe guru Wayne “Wobbly” Wright and welded up by Meads Speed Titanium, custom-built aluminum front and rear subframes, carbon fiber tail section and fuel cell, fully-adjustable Nitron suspension, braced billet swingarm, lightweight forged aluminum 17″ Dymag wheels, hydraulic clutch, and much, much more.
Mike says the “RZ500RR” weighs 100 pounds less than the standard RZV — about 350 pounds now! And with more than 100 horses on tap, the riding experience is unlike anything else on two wheels:
“To ride it feels like two 250cc motors strapped together (which it kind of is) but with more guts down low than you’d expect from a two-stroke… Two things happen simultaneously when it gets ‘on the pipe’ — the revs rise extremely fast and the front wheel reaches up towards the sky…
And then there’s the four-throated fury of this half-liter smoker on song:
Those quadrophonic pipes screaming and cropdusting everything behind it is hard to beat.”
Below, Mike gives a comprehensive rundown of this incredible two-stroke special. Photography credits go to Shaik Ridzwan. Enjoy!
Yamaha RZV500R Restomod: In the Builder’s Words…
This is a commissioned build and the overall design discussion, with the owner, initially centered around creating a Wayne Rainey Marlboro replica, but seeing as how those have already been done many times before, I proposed an alternative design — one that recalled the GP motorcycles that ran the Daytona 200 in the early 1980s.
The concept was to incorporate a combination of new, period-correct components in conjunction with custom-fabricated parts influenced by the design of those 80’s era race bikes. We steered clear of modern anachronisms. For instance the front end; instead of upside-down forks and radial brakes I opted for fully adjustable conventional forks, axial calipers, and fabricated a pair of full floating rotors that looked like they belonged on a mid 1980’s race machine.
The RZV500R came with an aluminum hand-welded chassis from the factory (all other versions had steel). New front and rear subframes were fabricated, but the central frame, although modified, still remains and the triangular pattern of the gussets is echoed in the billet rearsets and the inside faces of the swingarm.
Yamaha had some pretty wild engineering going on back in the day. The exhaust routing on the original bike essentially displaced the shock’s typical vertical layout and relegated it to a longitudinal position beneath the bike. Although that feature was retained on the build, all of the original heavy cast linkage and relay arms were remade in billet aluminum and coupled to a new fully-adjustable Nitron shock.
The uninspiring original aluminum boxed swingarm was redesigned in billet aluminum to resemble the over-braced style used by Grand Prix teams in the 80’s.
Pipe design is the single most important thing to get right on a two-stroke and just bolting on set of heavy, steel, aftermarket pipes was not really an option — for performance or visually. Two-stroke pipe guru Wayne “Wobbly” Wright in New Zealand designed and blueprinted these four custom chambers specifically for this motor’s uprated spec.
Bryce Meads of Meads Speed Titanium (also in NZ) painstakingly and artfully rolled and welded dozens of individual titanium strips into cone segments to complete this incredibly lightweight tuned system.
Due to their size and layout, the unique pipes necessitated a special one-off tail fairing to accommodate them. To keep the overall silhouette as slim as possible I borrowed from the look that some of the early Yamaha race bikes employed and fabricated a two-piece, carbon fiber tail unit. Assembled with quick turn fasteners it was constructed to wrap over the main chambers, yet allow the stingers to exit through it at the back.
The overall shape and lines of the original fuel tank served as the basis for molding a redesigned fuel cell out of carbon fiber and incorporates a billet endurance style dry break filler.
The cable clutch was upgraded to a hydraulic unit.
The original RZV came with 16 and 18” heavy cast wheels. Dymag produced many of the high performance racing wheels for GP teams of the 80’s era and fortunately they still offer the same vintage three-spoke style now and in lightweight forged aluminum. And the upgrade to the industry standard 17” wheel size also allowed us to run modern tire sizes.
The original RZV weighed 450+lbs (204kg). As is always the case with the bikes I build- considerable effort is made to lighten the machine as much as possible. Featherweight Li-Ion battery replaced the lead acid original, the wiring was pared down to only the necessary circuits. Steel components were replaced with fabricated aluminum or titanium pieces and the bodywork is mostly carbon fiber. Even though we didn’t go to full race bike extremes (it’s still a street bike after all) we were able to lose over 100lbs (45kg) of weight.
Although the original donor bike was running, it was in tough shape. RZV500’s were detuned from the factory to a lowly 64bhp due to emissions. Additionally, a few ponies had already escaped from this bike in its nearly 40 year life. Once opened up, we found the motor had 3 out of 4 different sized pistons in it and the heads looked like a chopping block!
Wilson Performance handled the task of rebuilding and upgrading the motor to 100+hp spec (a number that we agreed would provide substantial performance and reliability). While the cases were split we also took the opportunity to road race cut the transmission for slicker shifting.
To aid the owner’s tuning duties, the original four outboard facing Mikunis were replaced with new, single circuit, metering rod carburetors, from Smart Carb.
To improve handling, the original narrow, spindly forks with Yamaha’s air-assisted, brake linked anti-dive feature were scrapped for Nitron fully adjustable conventional forks and a redesigned billet triple clamp with a more modern width and offset. A minimalist race dash was fabricated incorporating a Motogadget analog/digital multi feature tachometer and a standalone water temp. gauge.
Rather than enclosing the unique compact V4 motor behind full bodywork I leaned towards the 3⁄4 style fairings popular in 80’s endurance racing.
The bodywork is a heavily modified set of period Yamaha ‘race glass’ redesigned to accept another signature look from endurance racing, the single offset headlight.
The whole bike is an outright sensory experience to ride. Kick it over and it immediately crackles to life. The quartet of pipes ringing and popping with outright surliness; it just wants to be unleashed.
To ride it feels like two 250cc motors strapped together (which it kind of is) but with more guts down low than you’d expect from a two-stroke and everything is rather tame-ish below 7500 RPM.
Then two things happen simultaneously when it gets “on the pipe” — the revs rise extremely fast and the front wheel reaches up towards the sky. As for the rest: the brakes are just overkill for a bike this light and stop it instantaneously; the handling is very predictable and stable as it bends through corners, but those quadrophonic pipes screaming and cropdusting everything behind it is hard to beat.
To see a bike like this through wouldn’t be possible without the skill and help of some incredibly talented folks. Thanks to: Mark Atkinson, Max Hazan, Bryce Meads, Paul Taylor, Hitoshi Umekage, Bill Wilson.
Follow the Builder
Web: championshipcycles.com
Instagram: @championshipcycles
Photographer: @shaikridzwan”}]]
