Yamaha RD 250

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Yamaha
Yamaha RD 350 2011-01-29.jpg
RD 350 (1973)
Yamaha RD 250 (RD 350)
Manufacturer Yamaha engine
Production period 1973 to 1979
class motorcycle
design type Sports Tourer
Motor data
2 cylinders, air-cooled, two-stroke engine
Displacement  (cm³) 247 (347)
Power  (kW / PS ) 22/30 at 7,500 min −1 (28.6 / 39 at 7,500 min −1 )
Torque  ( N m ) 24.4 at 7,000 min −1 (37.2 at 7,000 min −1 )
Top speed (  km / h) 135-160 (160-170)
transmission 6-speed, multi-disc clutch in an oil bath
drive Chain drive with open roller chain
Brakes Front: disc brake Ø 267 mm, with two-piston fixed caliper, from 1978 single-piston floating caliper / rear: drum brake, from 1976 disc brake
Wheelbase  (mm) 1320
Dimensions (L × W × H, mm): 2070 × 835 × 1110
Seat height (cm) approx. 79 cm
Empty weight  (kg) 146
Previous model DS7 (R5)
successor RD 250 LC ( RD 350 LC )

The Yamaha RD 250 is an air-cooled two-cylinder two-stroke motorcycle by the Japanese manufacturer Yamaha , which was offered from 1973 to 1979.

history

The RD 250 was produced from 1973 to 1974, the RD 250 B in 1975, followed by the RD 250C in 1976 , which was produced until 1979. In its time, the RD 250 was one of the most powerful motorcycles in its displacement class that could be bought. These motorcycles are still used today in a modified and optimized form in classic car and club sport races.

features

  • Front fork with 34 mm stanchions
  • two struts in the back
  • Wire spoke wheels
  • 28 mm carburetor
  • Diaphragm inlet valves
  • 5 transfer channels
  • 30 hp (1973-74), 32 hp (1975), 27 hp (1976-79)
  • Separate lubrication via speed and load dependent oil pump

technology

engine

RD 350

The horizontally split motor was based on the previous model DS7. The inlet to the now 28-millimeter carburetor for each crankcase was controlled by diaphragm valves . The raised inlet channel serves as an additional transfer channel, Yamaha calls this principle torque induction .

An electric starter was not planned - the RD 250 was started with a classic kick starter .

The transmission had 6 gears; However, for some markets the sixth gear was blocked so that only gears 1 to 5 could be engaged. With the final gear ratio being extended at the same time, limit values ​​for noise emissions could be complied with.

Web links

Individual evidence

  1. ^ Hermann Novak: Yamaha RD. Accessed on January 30, 2011 : "The (almost) complete RD model listing"