Instruction manual

NOTE—Remember there is a paper washer under each oil pump end cap and, when

fitting a new paper washer to the front cap, ensure the oil passage in the

front cap is not obstructed by the paper washer.

Make certain that the guide screw pin is correctly located in its groove (cut in

the plunger) before tightening down otherwise serious damage will result when

the engine is revolved. NOTE :—The guide screw pin is inserted in the screw

relieved end first.

OVERSIZE PARTS AND RE-BORING CYLINDER BARREL

Pistons and rings, .020" and .040" larger than standard, are available. These degrees

of oversize make it essential for the cylinder barrel to be re-bored to accommodate them.

We can provide that service at prices quoted in the Spares List.

On the 350 c.c. the cylinder standard bore is 2.7187 ± .0005". The 500 c.c. cylinder

standard bore is 3.250 ± .0005".

When the wear at the top of the barrel reaches .008" the barrel should be bored out

.020" oversize and a new oversize piston and rings fitted.

Crankpin rollers .001" larger than standard can be supplied. We recommend only

skilled mechanics should fit these because it is almost general that the big-end journals

and sleeves require " lapping " to ensure a correct fit.

REMOVE SPARKING PLUG

Always exercise the greatest care to avoid thread seizure when removing a sparking

plug. If any resistance is felt, apply paraffin. Before replacing plug, it is desirable to

coat the thread with "O i l Dag" or Graphite paste. This will guard against seizure

upon subsequent removal.

PUSH ROD COVER TUBES

350 machines are normally not fitted with a compression plate. In that circumstance,

on each push rod cover tube there is one 011087 metal washer, 3/64" thick. This is

located BELOW the rubber top gasket. Also a similar washer is fitted on the top of the

rubber top gasket.

The compression plate 014839 can be fitted to the Competition 350 engines. This plate

is z 88·5 ot 1 ot 53·6 morf oitar noisserpmoc eht secuder neht siht dna ssenkciht ni ”

to 1, and when such a plate is fitted there is an additional 011087 metal washer fitted

on the top of the rubber top gasket, making a total of two in that location on each

cover tube.

All 500 c.c. engines are fitted with a compression plate which is 8" in thickness, and

each push rod cover tube then has one 011087 metal washer, 3/64" thick, located below

the rubber top gasket and one 014603 metal washer, 8" thick, located over the rubber

top gasket.

If, for any reason, the compression plate is dispensed with (increasing the compression

ratio from 6·00 to 1 to 7·24 to 1) the 014603 washer on the top of each rubber top gasket

is replaced with one 011087 metal washer, 3/64" in thickness.