Bridgestone 90
BRIDGESTONE 90
Road Impression
BONNEVILLE SALT FLATS provided our staff with the testing grounds for the Bridgestone 90. We put several hundred miles running around the lake bed and environment on the machine loaned to us by the importers/distributors of Bridgestone, the Rockford Scooter Co., Inc. For many it was the first view of the new 90, the latest appendage to the line of Japanese-made Bridgestone 50s, which, incidentally, are still being made and are available from Rockford.
Progress in engineering shows in the new engine, now cniploying the latest improvements in two-stroke design, in particular the rotary valve induction system. We repeat ourselves in pointing out that the singular advantage in con trolling the induction of the fuel/oil mixture into the engine via a rotary valve is simply that more of it can be inhaled in one cycle of the engine. Most noticeable improvement is in the lower rev ranges. an area of performance rarely very sparkling in small displacement en gines. Obviously, the more fuel available
for burning means more power, or in this case, torque, which is really more useful than the former.
Bridgestone claims several features that separate it from its competitors, among them superior power and torque. Another is the four-speed, rotary gearbox. "Ro tary", in this case, means that one simply continues pressing down on the shift leve' to select the next gear. The system places each gear, and neutral, one after the other so one may shift from first, to second, to third, to fourth, to neutral, to first, ad infinitum. One may fight the system by back shifting with the rear portion of the rocking shift lever, kicking down on the back to shift down.
Bridgestone also makes the tires found on the bike of the same name; in fact the Bridgestone Tire & Rubber Company is the largest tire maker in Japan and distributes them in this country through another company in the Eastern U. S. Subdued black in finish, the 90 almost escapes notice. Its almost complete silence of operation adds to its innocuousness. A
brightly colored paint job might help; it would seem the proper solution in place of a loud exhaust system. Of course. some people just might like riding this quiet, restrained vehicle. We did.
Power is 7.8 hp at 7,000 rpm. Top speed is stated to he 60 mph; we were able to hold a steady 57 at Bonneville, on a rela tively new machine that was not in the best of tune considering the rather strange atmosphere prevalent on the salt flats. This speed was measured, incidentally, by the speedometer, an instrument of not al ways consistent accuracy. Acceleration is on a par with another Jap~nese make of similar sDecifications.
Standard equipment includes folding rear pegs, tool kit, neutral indicator light, rear view mirror and luggage rack. In teresting technical details: bore/stroke of 1.97 inches x 1.77 inches: magneto igni tion; 5.12 square inches of brake area; 174 pounds dry weight; and overall length of 72 inches. The latter dimension adds up to six feet; Bridgestone packs a con siderable bargain into so short a space.
