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/126435
II --.. - -_.....BI ES TRANS-USA c. 'i. a .£2£1• • •_ Honda RC500 Honda now jumps on the bandwagon with its own unique design of works bike rear suspension_ Labeled the AIE-H, Honda's new variable leverage ratio rear suspension is not a new or original idea, but Honda has executed the design better than anyone else. 'The idea is to provide a higher leverage ratio and thus softer shock damping when the rear suspension is extended, and a lower leverage ratio and firmer dampening as the suspension becomes compressed_ This way conventional rear shocks which are speed/force sensitive, also become position sensitive for th~oretically more perfect rear wheel control. And along with its all new rear suspension is a cOfl!pletely new'motorcycle to go with it. To begin with there is now a twin downtube front frame like on the RG 250 works bikes, replacing the single downtube front frame that has been on all previous Honda works motocrossers. This new frame is supposed to offer more rigidity than before. Perhaps the strangest change of all is the switch from Showa, the firm which has always supplied Honda with its suspension parts in the past, to Kayaba. The front forks are KYB air/spring works units with 280mm of travel. Rear suspension travel is 300mm, provided surprisingly by production KYB reservoir deCarbon shocks as found on RM Suzukis. The new bike is extremely light at 216 pounds even with heavy Metzeler tires, thanks to an ample supply of titanium parts. :rhe bike abounds with unique engineering innovations and machine crafted designs that can leave you marveling' for hours. One of the neatest tidbits is a cast folding aluminum shift lever with special integral molded rubber spring. The engineering and die manufacturing costs of this little jewel had to be astronomical. To go along with that all-new chassis is an all-new H-type engine design. Many have felt the World Championship winning RC 450 engine was much too excessive and the new H-type engine proves this with a reduction in displacement to approximately 400cc. A chrome plated bore aluminum cylinder is used in conjunction with a CR 250R2 Keihin 36mm carb and 6-petal reed valve assembly which means this new motor does not need to tum a lot of RPM to produce horsepower. The powerb'and is also a broad one since only a 4speed transmission is housed in the miniature magnesium engine cases. Rider Steve Wise claims only 2nd and 3rd gears are used for the majority of tracks, 1st gear comes into use for very tight turns and 4th gear is very seldom used. Honda may not be winning too many races in America in the 500cc class with this new RC 500 class bike because they lack a competitive 500cc class rider, but the innov.ative and all new AIE-H works motocrossers show once again that Honda can build what is probably the best bike when they put their mind to it. • (Above top) Honda's 1980 production CR 250R3 features new twin downtube frame and Showa reservoir shocks.IAbove) New works 400cc motor is a masterpiece of engineering design. Steve Wise models the new RC·500 class bike with variable leverage action rear suspension. (Continued next week) 17