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The publication of this story would not have been possible without the permission of the author, Alan Cathcart...... thanks again Alan.
KENNY ROBERTS: “That Was the Good One!” by Alan Cathcart
Twenty years on, Kenny Roberts remembers the OW48R as
the best of the in-line piston-port YZR500 Yamahas he rode to his trio of 500cc
World Championships in 1978-80. “The reverse-cylinder bike had a little bit more
midrange, because of the straighter exhaust pipes,” he says. “That was the main
reason they reversed the two outer cylinders, to give a straighter run to those
two pipes, plus more room for the middle two down below. Turning the two outer
carbs around made sense, and it worked once they found a way of fitting it in
the aluminum chassis.”
How did the OW48R compare to its Suzuki and Kawasaki rivals? “The thing about the Yamahas is that they were piston port, so they simply weren’t as fast as the Suzukis and Kork’s Kawie, which were both disc valve - the piston port was at the limit of its horsepower, so 1980 was the last roll of the dice for that kind of an engine. But the nice thing about the piston port was that it actually worked well around the race track - it moved the bike well. On some tracks, the Suzukis were hard to beat, on account of their top speed, plus you couldn’t just gas the Yamaha wide open exiting a turn, else it’d die on you. Hairpins were really tough, because you had to bring it down low to get it out of a hairpin, and with the tyres we had back then, you couldn’t clutch it out of the turn to get it back in the powerband. If you had a bunch of Suzukis in front of you, they’d make you feel bad by pulling two bike lengths on you out of there . Hartog used to tell me he’d open the throttle wide open on the Suzuki at 5000 rpm exiting a turn, and it’d run right out of the corner - but you do the same thing on the Yamaha, and you ain’t going nowhere! Even if you opened it at 9500 rpm, you weren’t going places - but when you got it pushing hard out of a corner and had it running up around 10,000 rpm, it had very usable power, and was a pretty nice motorcycle to ride. But, 12,000 rpm and it was all done - overevving just wasn’t a part of the ball game back then, so you had to take care to get the gearbox set up just right to handle that, and accept that at some race tracks, the bike just wasn’t going to be as good as at some others. But, overall I thought it was a really good motorcycle - and it was a long time before we had something better to ride!”
How so? “Well, the disc valves that Yamaha built after that just didn’t work. The closest was the OW60 square four, which I rode right at the start of the ‘82 season - got pole in the Daytona 200 before it ran a crank bearing, and I won the opening GP in Argentina with it. But then we came to Europe and they gave me the V-four, the OW61, and we had nothing but trouble with that all year. They had built the flywheels a little too light, and it would burn up tyres, plus there was no bottom end power, they had the first push-pull carburettors that gave you no idea when it was all gonna happen, and it had that weird laydown sideways shock that never worked. That was a handful all year to try to ride, and we’d probably have been faster on the two-year old OW48R piston port, which while it wasn’t so fast, was much nicer to ride.”
How about the chassis of the 1980 bike? Did it handle
that much better with the aluminium frame? “I’d say it was as good as anything,
though it was because Suzuki kept shooting themelves in the foot that it won the
championship, as much as anything. I thought their bike was good enough to win
the title, but they had four or five riders on the thing who kept beating each
other, whereas I could just cruise around and win a few, come second or third in
the others, and beat everyone I had to in order to win the championship. They
made it easy for me.”
Kenny’s OW48R always had brake cooling ducts on it, the only one to do so. Did that mean he had problem with overheating the brakes? “Well, I always had big brakes on my bikes, even on my 250, and the problem was that in those days Yamaha made their own stainless steel brakes, and they were horrible! I don’t think you’d ever finish a race with the lever the same as when you started, and at Daytona for example you had to take it real easy with the brakes, otherwise you’d run out before the end of the race. Best thing that ever happened to Yamaha was in ‘83 when we went to Ohlins and Brembo - the shock was just a huge step forward, because we always had trouble with the long monoshocks they used before that. Because they had so little oil capacity, it’d heat up quite a bit if you really rode ‘em hard, and the thing would get sorta out of control. Having the exhaust running so close to it before they made the reverse-cylinder bike didn’t help, but you gotta remember the racetracks were a lot more bumpy back then than they are nowadays, so the shock would take a good workout in a race, and if it didn’t hold up, you were in serious trouble. You had so many problems with the rear suspension, you didn’t really worry about the front - the forks were nothing special, they just held the wheel and worked.”
What was the best year of Yamaha that The King ever rode, the one that gave him most satisfaction to ride? “For a bike I could actually use really hard, which for sure was the best bike they ever made for me to race, it’d obviously be the ‘83 - the last one I rode, which was the first with the Deltabox frame, that was finally strong enough to handle the power delivered by the engine. But the 1980 OW48R was a good motorcycle to ride - the one with the first aluminum frame. When we were testing it at Misano, there’s that big banked horseshoe behind the pits, and I could stick it in there so hard that even though you could feel the frame flexing, right in the middle of the corner it’d like sorta catapult itself out of there. I could actually go round that corner faster than the frame was capable of going, just because I had the grip and it was a bike that simply worked right. It was the first light 500 that Yamaha made and the aluminum chassis just took out all the vibration. It was actually one of the best bikes I raced, that 1980 - which is why I have one at home, just like the one you tested. It was a good motorcycle - probably the best in-line four Yamaha ever produced.”
Alan Cathcart
03/23/08 06:37 AM +1000
This website © Greg Bennett 2002.
This article and images © Alan Cathcart 2000.
