Motor-cycling

Press, Volume CXV, Issue 33987, 30 October 1975, Page 20

Motor-cycling

Yamaha unveils its new range of four-strokes

A new range of highperformance fourstrokes — including a shaft-drive, three-cylin-der model with a double overhead camshaft — has been announced by the Japanese Yamaha factory.

This provides the substance to the rumours circ u I a t i n g some nine months ago that at least one of Japan's two-stroke specialists was contemplating greater concentration on the use of valve motors. In a major styling change, the company is also equipping its street range, from 400 c.c. upwards with the exception of the XS6SO single overhead camshaft twin, with cast aluminium wheels and disc brakes front and rear. The ever popular RD3SO twin two-stroke continues in a new guise. The engine has been increased to 400 c.c., although the reedvalve induction system and the close ratio six-speed gearbox remain unchanged. There have been styling changes and the machine is now equipped with cast wheels and a rear disc brake as standard. But in future there will be a choice of two-stroke or four-stroke in the middle range. As well as the RD4OO, there is a new 360 c.c. four-stroke twin. Intended as a commuter bike, it will be known as the XS36OC. The most impressive of the new models is the delux XS7SOC, a three-cyl-inder, four-stroke which drives through a shaft. It has discs front and rear and, of course, the sevenspoke cast wheels. The ex-

haust is of the three-into-< one variety. The four-strokes have not been restricted to just the street range. There are two new 500 c.c. four-stroke “thumpers” in the off-road range. There is the TTSOOC “racer” version and an XTSOOC enduro. Both bikes are powered by single overhead camshaft engines with magnesium side covers. There are nitrogeno i 1 , f o r w a r d-mounted shocks on the rear and long travel air-oil telescopic forks at the front. The dry weight of the enduro is only 2601b5.

Another new addition to; the Yamaha dirt bike; offering is the IT4OOCi enduro, which has mono-; cross suspension and a| two-stroke, single-cylinder I engine. There is also a new!

tiddler racer, the YZIOO, which is also monocross suspended Other dirt machines in the 1976 range are the more familiar YZ 250 and 400 c.c. models and a variety of MX (with standard suspension) motocross models and two trials machines, the TYI7S and the TY2SO. There is also a new 175 c.c. YZ moto-cross machine.

The street range begins with the economical stepthrough Chappy Then there is the RS 100 single and a pair of two-stroke twins, one of 125 c.c. and the other of 200 c.c. with an electric starter. As well as the new roadsters, the eight-valve XSSOOC re. mains in production.