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/126322
ational Championshipequipment Part II: The 250cc's By Jim Gianatsis A look at the results of the 250cc Nationals run thus far might leave you with the impression that there's just one bike capable of winning. But as good as the works Yamaha OW 38 is, it shouldn't be forgotten that it's the riding ability of Bob "Hurri - ' cane" Hannah which accounts for his domi nation of the 250cc 18 class this season more than anything else. ' It is int eresting to not e that two of th e most competitive designs , th e works Yamahas and th e works / production Hondas, are nearly complete opposites when com p a ri ng their construction and performance. The Yamahas P~vl; . ~Io~e , ., tll. th e shortest suspension travel whi le the Hondas are at the opposite end of the scale with nearly the longest. The Hondas have the pipey , quick revving and explosive powerbands with probably the most horsepower of any of the factory machines. T he Yama has , on the other hand , concentrate on a tractable low revving powerband at the expense of maximum peak horsepower. Each bike might be favored on a particular track . but more logically it would seem a high -horsepower engine would work better in a shorter suspension equipped chassis for fast smooth tracks . while tractable power and long suspension would be the trick setup for ro ugher co urses. Bu t because of their differences the Honda and the Yamaha neatly balance out , particularly when Bob Hannah and Marty Tripes , who differ radically in riding styles a nd 60 pounds in weight. are doing the rid ing . Yama ha OW 38-B-810 A new al l-tube frame with shorter DeCarbon monoshock , replacing t he semi -rno nocoq ue frame and longer production style monoshock of the past OW 25 works Yamaha is one of t!t~ . ~ost_ ~i~ i.fica nt . changes in the newer OW 38 bike n ow being used this season. The change was mainly made to allow increased air circulation around the Yamaha -built shock with reservorr. The front forks are prototype Kayabas with air/spring suspension. The monoshock uses a progressive rate coil -over spring and is easily adjusted for ride height . dampening, and even increased travel if wanted . Present suspension travel is 10.5 inches on each end of Bob's b ike. Also new is the engine which has smaller magnesium cases to reduce weight. The center-port chrome cylinder uses reed induction , an internal rotor CD I provides spark to the combustion chamber which displaces 246 cc. Other goodies include a full -floating rear brake, magnesium hubs . rubbermo unted handlebars . hollow axles. T im ken tapered roller bearings in the steering head . and a complete-up weight of 193 pounds when delivered ,fro m J apan though now it's increased to 198 pou nd s with heavier duty tires. Honda CR 250-78 or RC Type IIC It takes a trained eye and a lot of prying questions to figure out who is riding what kind of bike , production