With RZ500s becoming somewhat of a rarity, the Japanese import RZV500R makes an ideal alternative boasting a number of upgrades and easily fixable restricted power... Photography: Heather Ware, Alexandra Cooper
I have to admit that I am a certified RZ nutter. My first road bike was an RZ250FN and I’ve had a few RZs over the years as well as RDs. I’ve had an RG500 but one bike I’ve never owned that I have lusted after since I was 16-years-old is the mighty RZV500R. I recently restored this one.
RZ500s are getting harder to come by these days but a good alternative is a Jap import RZV500R, the alloy framed Japanese domestic mode – which is more readily available with low kilometres and will set you back around $$20,000 – $30,000 AUD. A rough one that needs work, $15 – $20k.
The RZV500R features upgrades not found on the RZ500N such as the hand welded alloy frame, braided brake lines, air assisted forks with rebound adjustment, cast alloy brake and gear levers, alloy clip-ons and different graphics.
The entire package weighed in at 9.1kg less the steel framed model. But sadly for the Japanese, the RZV was restricted to an underwhelming 64hp thanks to restricting the internal diameter of the exhaust pipes and with jetting. This is an easy fix… exhaust restrictors removal and jetting are all that is required and there is plenty of info available on various forums and pages.
Aside from the above changes the RZV500R is mechanically the same as the RZ500N we received here. The 50-degree V4 twin crankshaft two-stroke engine was seriously trick in its day but also overly complicated. The GP YZR500 featured rotary disc induction like the successful RG500 Suzuki.
Yamaha chose to go with reed valve induction and a YPVS powervalve system to broaden the powerband of the RZ500. The lower pair are fed through crankcase reed and the upper pair via the cylinders in a traditional piston port setup. It’s really weird but works, the power is very broad.
The Mikuni round slide carburettors are mounted on 90º manifolds on the sides of the engine behind the fairings and have complex cabling and a restrictive airbox shape. The lower expansion chambers exit normally, under the engine, but the rear cylinder pipes are complex and cross over each other to achieve tuned length and then exit under the tail unit. It’s a bit like a plumber’s worst nightmare!
The dual crankshafts are geared directly to the clutch and there is a counter-balancer driven off the front crank on early models and then the rear crank from 1985. Timing these is crucial when reassembling the engine.
The gearbox in the RZV500R is a large, over-engineered six-speed close-ratio unit with cassette-style removable cluster and unusually the outer main bearings and a separate troichoid oil pump lubricates the gearbox. Two-stroke oil is injected via Yamaha’s Autolube system.
Chassis-wise the RZ500 is also complex. The forks on the RZV are air assisted with hydraulic anti-dive and prone to fork seal leaks. The rear shock is horizontally placed under the engine and uses the lower crankcases as a mounting point.
The front wheel is a tiny 16in and rear a huge 18in. This is because the under seat area is occupied by the YPVS servomotor, battery and rear exhausts.
We will run a comprehensive rebuild and restoration guide to both the RG500 and the RZV500R in the near future. I enjoyed doing both bikes but the RG500 was by far the simpler and easier task. The RZV500R is complex and time consuming. Once finished though, I was happy with the result and the bike absolutely screams thanks to precision rebores by Serco and some extra time spent setting up the carburettors. I was really surprised, it is just as quick as my RG500…
YAMAHA RZV500R QUICK SPECS
Engine: 499cc liquid-cooled 50-degree V4 two-stroke
Claimed power: 90hp (64hp Japan RZV) (64kW)@9500rpm
Claimed torque: 50ft-lbs(65Nm)@8500rpm
Chassis: Hand welded aluminium frame
Dry weight: 196kg Fuel capacity: 22L
Suspension: 37mm telescopic forks with anti-dive, rear preload and rebound adjustable underslung monoshock Front brakes: Dual 267mm rotors with twin-piston callipers.
1984 – 1986 YAMAHA RZV500 GALLERY