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1973-74年Yamaha DT 250

2013/2/17 6:36:00

Make Model

Yamaha DT 250

Year

1973-74

Engine

Air cooled, two stroke, single cylinder,

Capacity

246
Bore x Stroke 70 x 64 mm
Compression Ratio 6.8:1

Induction

 

Ignition  /  Starting

Flywheel magneto

Max Power

32 hp @ 8700 rpm

Max Torque

2.4 kg-m @ 6000 rpm

Transmission  /  Drive

5 Speed  /  chain

Front Suspension

Rear Suspension

Front Brakes

Drum

Rear Brakes

Drum

Front Tyre

3.00-21

Rear Tyre

4.00-18

Wet-Weight

123 kg

Fuel Capacity 

9 Litres

The Yamaha DT series with monoshock rear suspension was introduced for the 1976 season following the success of similarly-equipped machines in world-championship moto-cross. Always confusing, the initials intended to identify the function of many Japanese bikes,

Yam-ahas included, in fact follow a wayward logic. Thus DT, which might fairly be interpreted as Dirt Track, is intended apparently to signify Dual use. (Where T comes in is not entirely clear, though Track makes reasonable sense, of course.)

A couple of years on from the original monoshock frame, that one a compromise affair evolved from the earlier pivoted-fork layout, the DT's frame was purpose-built to accommodate the cantilever system: thus the seat was only averagely high, instead of being suitable only for super-fit riders of over 6ft, who in any case appeared never to relax from a standing-on-the-rests position, and engine accessibility was improved. The spring unit, running parallel to the tank tube, was made under licence from De Carbon and combined the use of inert gas filled with hydraulic fluid.

The engine was fitted with the case-reed induction system, had none of the, harmonic balancers reckoned to be essential for the smooth running of purely 'street' machines, and turned out plenty of power which, while not angled towards on-road use (there was, for instance, a tendency to backfiring on closed throttle), made the DT a useful, not-too-noisy 65mph tarmac cruiser.
In the rough it was too heavy, and not powerful enough, to be a serious competitor; among half-serious trailsters, though, it stood out as a leader.