Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/126509
(Top line from left) Mike Bell on the new OW5O; Bob Hannah on what is basically last year's works bike; Larry Wosick aboard a VZ2SOH. (Middle IeftI A closer look at the OW shows how long the seat is. (Middle right) Swingarm leverage ratio is changed and shock runs through a tunnel in the airbox. (Bottom from left) WatereooIed engine appeers to have yz H features plus Power Valve. Air-adjustable forks flank a small radiator. Impeller housing sits ahead of clutch. By Mark K a r i y a - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 18 It's generally accepted that 125cc motocrossers must be watercooled to stay with the competition, both on the track and in dealer sales volume. Open class bikes, on the other hand, have such vast quantities of power that power losses toward the end of 45-minute motos simply aren't missed, There seem to be mixed feelings on the merits of watercooling in the 250cc class, though. Honda introduced a watercooled RC250 at the Anaheim Supercross in 1979, and its latest production 2505 are, of course, watercooled. The bikes that Honda has raced in the first three events this year, however, were air-cooled. Kawasaki's past works bikes and all their production machines have been air-cooled, yet their all-new team 2505 are watercooled. Suzuki has stuck to air-cooling their 2505, even their latest slim and speedy works bikes. Yamaha's factory 2505 seem to be evolving along the same lines as Kawasaki in that their present bikes are now watercooled and look to be quite a departure from what was campaigned last year. Mike Bell was the first Yamatia teamster to receive a new OW50 which he rode to third at Anaheim, second and fourth in Seattle. The new Yamahas apparently are just trickling in from Japan. Bob Hannah had one in his pit area Sunday at Seattle; he had ridden the bike (though not at Seattle) in practice, but would race the "old" bike, last year's machine, as did other team members. They, too, should be receiving their new water-pumpers within the next few weeks, perhaps in time for Daytona. Whether watercooling is better in Supercross is debatable. In the three races this year, Suzuki's air-cooled bikes have been acknowledged as the fastest and probably best handling. When the Nationals roll around, though, things may change with the long 45-minute motos and open courses. Attempting to glean details on the latest OW proved to be just that - an attempt. Yamaha's Racing Team Manager Ken Clark said, "1 can't tell you any more than what you can see externally, We don't release engineering data on works motorcycles." OK, that's understandable. When you let the competition know your trade secrets, they aren't secret anymore. Why let them in on what you've worked hard to Ieam and achieve? What we'll do here is let you look at the Yamaha OW50 just as we did in the pits.