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Yamaha RD 250LC

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Model

Yamaha RD 250LC / RZ 250LC

Year

1981

Engine

Two stroke, parallel twin

Capacity

247 cc / 15.0 cu-in
Bore x Stroke 54 х 54 mm
Cooling System Liquid cooled
Compression Ratio 6.2 :1
Lubrication Autolube
Oil Capacity 1.6 Litres

Induction

2x  Mikuni VM28 SC carburetor

Ignition 

CDI
Starting Kick

Max Power

35.5 hp / 26.1 kW @ 8500 rpm 

Max Torque

30.2 Nm / 3.1 kgf-m@ 8000 rpm
Clutch Wet multi-plate

Transmission

6 Speed 
Final Drive Chain

Front Suspension

Telescopic forks

Rear Suspension

Monocross

Front Brakes

Single 267mm disc

Rear Brakes

Drum

Front Tyre

3.00-18

Rear Tyre

3.50-18
Dimensions Length 2080 mm / 81.8 in
Width    750 mm / 29.5 in
Height 1090 mm / 42.9 in
Wheelbase 1360 mm / 53.5 in
Seat Height 785 mm / 30.9 in
Ground Clearance 165 mm /  6.4 in

Dry Weight

139 kg / 306.4 lbs

Fuel Capacity 

16.5 Litres /  4.3 US gal

Consumption Average

40 mpg

Standing ¼ Mile  

14.6 sec

Top Speed

98 mph / 157.7 km/h
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This was a supersport model developed with the TZ250 as its base. It immediately created a big sensation after its stunning debut at the 1979 Tokyo Motor Show. Its liquid-cooled 2-stroke, 2-cylinder engine pumped out high power equivalent to 140 hp per liter of displacement.

This was mounted on a double cradle frame with a Monocross suspension and other features like lightweight cast wheels to produce unprecedented running performance. Even today it remains a legendary model with a devoted following.

Almost as quick as its 350 brother, the 250LC earned extra notoriety in 1980 with a top speed in excess of 100mph. Fond parents said that selling a 250 as fast as this was tantamount to Yamaha inviting the (British) nation's youth to commit hara-kiri in the run up to the L-test. It all added up to a very effective send-off for the LC, which (of course) became overnight the learner's favourite bike.

Based — but very loosely, like the 350LC — on the layout of Yamaha's five-year-old watercooled racers, the 250 had a reed valve as an aid to easy induction and separate barrels where the competition TZ had had the pair as one unit; an obvious similarity was the water impeller driven from the right end of the crankshaft. Ports were smaller on the road bike, as were the Mikuni carburettors.

 Cylinder head design, too, was different.
But in concept, and looks, the LC displayed much of the racer's style. Its performance was ahead of that of the earlier air-cooled RD, which in its day was reckoned to be king of the 250s, in speed if not in sales.