Engine Data

Technical Data.

Engine Type.

Inclined twin cylinder piston-port 2-stroke, water cooled with oil pump lubrication.

Displacement 656cc.

Bore Stroke 76mm x 72mm

B.H.P. at RPM 48 @ 6,000

Max Torque 45 ft lb @ 3,000 rpm

Carburettor 34mm mk1 36mm mk2 early 38mm mk2 with the later porting



Lubrication Silk duplex micrometering pump fed from seperate oil tank.



Fuel Air ratio 50:1 approx



Ignition Lumenition

with centrifugal advance and retard.
Twin 6v coils in series.



Ignition Timing Mk1 7mm BTDC Mk2 5mm BTDC

Late Mk2 7.6mm BTDC



Spark Plugs NGK B8HS



Exhaust Siamese Expansion Type.



Transmission

Primary Renolds Dupex 0.437 roller chain



Clutch 6 plate running in oil mist, Or 7 plate Triumph conversion



Gearbox Four Speed



First 2.2T
Second 1.59
Third 1.21
Top 1.1



Final Drive Renolds 5/8" x 1/4 roller chain Rear Sprocket 36 Teeth

Front Sprocket 17 Teeth Alternate 15 or 16 Teeth