Yamaha RD350

Yamaha RD350
Manufacturer	Yamaha Corporation
Production	1973–1975
Predecessor	Yamaha R5
Successor	Yamaha RD400
Class	Sport bike
Engine	347 cc (21.2 cu in) air-cooled, two-stroke parallel twin
Bore / stroke	64 mm × 54 mm (2.5 in × 2.1 in)
Compression ratio	6.6:1
Top speed	105 mph (169 km/h)
Power	39 bhp (29 kW) @ 7,500 rpm
Ignition type	dual coils, breaker points
Transmission	6-speed manual
Frame type	Tubular twin cradle
Suspension	Telescopic forks; dual shock absorber rear
Brakes	Front: disc (Indian RD350: drum); Rear: drum
Tires	Front: 3.00x18-4PR; Rear: 3.50x18-4PR
Rake, trail	27.5 degrees, 104 mm (4.1 in)
Wheelbase	1.320 m (4 ft 4.0 in)
Dimensions	L: 2.04 m (6 ft 8 in); W: 0.835 m (2 ft 8.9 in); H: 1.11 m (3 ft 8 in);
Seat height	800 mm (31 in)
Weight	155 kg (342 lb) (wet)
Fuel capacity	15.5 L (3.4 imp gal; 4.1 US gal)

The RD350 is a two-stroke motorcycle produced by Yamaha from 1973 to 1975.^[2] It evolved directly from the piston port (pre-reed valve intake tract), front drum-braked, five-speed Yamaha 350 cc "R5".^[3]

The engine is an air-cooled, parallel twin, six-speed (in some markets, such as the UK, the first model was sold in five-speed form), reed valve-equipped intake tract two-stroke engine. The bike is usually referred to as a sport bike.

All models were equipped with "Autolube" automatic oil injection, relieving the user from the need to mix gasoline and two-stroke oil.^[2]

Rim sizes are 18" WM2 (1.85") front and 18" WM3 (2.15") rear, both being of chromed, wire spoked steel construction. In the UK, rim sizes were 1.60 front and 1.85 rear.

Brakes are: single front disc brake and a rear drum brake, a combination described by Cycle Magazine as the best in its class.

The frame dimensions of the street 350 are very similar to the Yamaha TZ 250 and TZ 350 series factory road race bikes, differing mainly in weight and front fork rake – the RD being ~27 degrees and the TZ being ~25 degrees. The frames appear similar, side by side, with the street frame adorned with many brackets for the street equipment. The weight difference is substantial though, with the street-going RD frame weighing almost twice as much as the "TZ" roadrace race frame.

The stock bike made 39 bhp (29 kW) (32 bhp (24 kW) at the back wheel) at 7500 rpm^[1] – very fast for the time. A contemporary of the RD is the Kawasaki H2 750cc Triple that produced 74 hp.

The 350 evolved into the more refined and cleaner running RD400C in 1976, the "D" and "E" in 77–78 and the final model, the white 1979 RD400F.

The RD350B in India

A licensed version of the RD350B was assembled in India between 1983–1990 by Escorts group under the brand name Rajdoot 350. It did not repeat the success of the RD350B in the Indian market, which some attribute to a high purchase price and poor fuel efficiency. However, it established Rajdoot/Yamaha as a performance bike manufacturer in India. There were two models for the Rajdoot 350 - High Torque and Low Torque. Compared to the Yamaha RD350B that made 39 bhp (29 kW) at the crankshaft, the 'High Torque' version made 30.5 bhp (22.7 kW) and the later 'Low Torque' made only 27 bhp (20 kW), the engine being detuned in the quest for better fuel economy. By the time the production ended in 1990, the bike was nearly 100% sourced in India, with very little Japanese parts content.

Brakes are: 180mm dia drum brakes front internal expansion (twin leading type) and rear single internal expansion.

The RD350 was the first sporting motorcycle built in India, and it still enjoys cult status, with many RD clubs around the country. Around 7000 were made at the end of 1990.^{[citation needed]}

References

^ ^a ^b ^c ^d McDiarmid, Mac (1998). Classic Superbikes From Around the World. Paragon. pp. 78–9. ISBN 1405427167.
^ ^a ^b Smith, Robert (January–February 2010). "Yamaha RD350 - Classic Japanese Motorcycles - Motorcycle Classics". Motorcycle Classics. Retrieved 2017-09-18.
^ Richard Backus (November–December 2009). "Yamaha R5 350 Twin". Motorcycle Classics. Retrieved 2009-11-11.