A Quality Works RZ250R custom that lets you fully enjoy the unique charm of a 2-stroke. A classic motorcycle exploration: Yamaha RZ-R edition [2/3]

Hop → Step → Jump

When I think of the two-stroke parallel twins that Yamaha sold in the 1980s, the 1980 RZ250/350, the 1983 RZ250R/350R, and the 1985 TZR250 (1KT), I get the impression that they were all about hop, step, and jump.

Although this expression makes it seem as though the original RZ and RZ-R were the run-up to the birth of the TZR, it’s difficult to simply rank the three cars, each with its own unique appeal. That said, compared to the TZR, which is light and gentle and looks like anyone can drive it fast, the original RZ had a peaky characteristic that tested the rider’s skill, and while the introduction of YPVS made it easier to handle, the RZ-R, with its heavy weight and long wheelbase (145kg, 1385mm; the original RZ was 139kg, 1355mm, the TZR was 126kg, 1375mm; weights are dry), seemed to lack the sharpness of a two-stroke sports car…

But that’s only true for the stock model, and unlike the TZR, which is highly finished and has limited scope for modification, the original RZ and RZ-R can be transformed by customization. I thought I was aware of this fact from my previous reporting experiences, but the ride quality of the RZ250R custom built by Quality Works as a demo vehicle exceeded my expectations.

Easy to handle, even for beginners

Before I give my impressions, let me give you an overview. This bike, built by Quality Works, is based on the 1AR produced between 1984 and 1985, but it’s a fully customized bike with almost no stock parts. The engine is a 347cc model (maximum output is approximately 65ps) that uses pistons and cylinders from the RZ350R, and the suspension has been completely revamped using later model genuine Yamaha parts and aftermarket parts. So, what were my impressions after riding this bike over a variety of terrain, mainly mountain roads?

The first thing that impressed me was the ease of handling and sense of security that even a beginner could easily ride. Conversely, the stock RZ-R’s suspension feels lacking by modern standards, and the RZ350R’s 55ps engine power clearly exceeds the vehicle’s tolerances, but this vehicle can attack corners with a feeling that is at least on par with the latest sports models, and it is also able to cruise leisurely using the low and mid-range RPMs quite naturally. The main reason for this is probably the perfectly set-up suspension and carburetor (previously it was fitted with a φ33mm, but now it has been deliberately opted for a φ28mm, prioritizing ease of handling).

However, what impressed me even more was how the aforementioned lack of sharpness has been completely eliminated, and the unique appeal of a two-stroke road sports bike has been greatly enhanced. What particularly caught my eye was the intense acceleration that felt like warping when it entered the power band above 7000 rpm (on mountain roads I couldn’t wait for the straights), but the wonderfully faithful response to throttle operation is unique to a two-stroke, where the piston explodes with every stroke (four-strokes explode with every two strokes), and the lightness you feel when leaning the bike into a corner is also unique to a two-stroke, where there are no cams or intake or exhaust valves on top of the engine.

I think the reason I felt this way was because of the ease of handling and sense of security I mentioned earlier. In other words, the Quality Works RZ-R has created an environment where you can enjoy the appeal of a two-stroke, and has further refined the appeal of a two-stroke.

Consider the engine’s characteristics

As an aside, I own a 1986 TZR250, and after tinkering with it, the maximum rear wheel output at its best is 55ps, but during this test ride I realized that the RZ-R and TZR deliver power in different ways. Of course, Quality Works’ custom bike has a 347cc displacement (the TZR cannot be expanded to that extent, with a maximum of around 270cc), so a simple comparison isn’t possible, but while the TZR delivers power smoothly and smoothly, the RZ-R has a powerful feel that I’d describe as punchy (and I’m not being rough about that).

One possible factor behind these differences is the engine’s bore x stroke and crank web (bore x stroke: RZ250R: 54 x 54mm, RZ350R: 64 x 54mm, TZR250: 56.4 x 50mm, with the longer the stroke the larger the crank web). In addition to that, the difference in intake system – the RZ-R has a piston reed valve, while the TZR has a crankcase reed valve – may also be having an effect.

Half happy and half sad

After the test drive, I felt half happy and half sad. That is to say, I was extremely happy to have realized the potential of the RZ-R and to have rediscovered the appeal of two-stroke sports bikes. But at the same time, I began to feel sad that the history of two-stroke sports bikes came to an end at the end of the 1990s.

However, the used market price for RZ-Rs hasn’t risen as much as the original RZ, and there are still many reproduction and tuning parts available. Also, Yamaha itself seems to consider its traditional 2-stroke parallel twin an important asset, and compared to other vehicles of the same era, the supply of genuine parts for the RZ-R is in a good category. In other words, the hurdles to acquiring and maintaining a RZ-R are not particularly high, so considering these facts, there may be no need to feel disappointed.

Detail explanation