Instruction manual

TO REMOVE THE PETROL TANK

Close both petrol taps and disconnect the petrol feed pipe from each tap. (Use two

spanners, one to hold the tap and the other to unscrew the union nut on the petrol pipe.)

Cut the wires interlacing the four fixing bolts.

Unscrew the tank fixing bolts and the tank is then free to be taken away.

NOTE—The disposition of the various rubber and metal washers and tubular spacers

should be specially observed so that they may be correctly replaced.

TO REPLACE THE PETROL TANK

Proceed in reverse order to removal. Screw firmly home the four fixing bolts and

interlace them, in pairs, with 22 gauge copper wire.

TO REMOVE THE ROCKER BOX

Remove the petrol tank.

Remove the three nuts and fibre washers retaining the rocker box side cover and take

away the cover.

Disconnect the oil pipe feeding oil to the rocker box.

Turn over engine until both valves are completely closed.

On 500 c.c. model, remove engine steady bracket by removing bolt from frame clip and

nuts and washers from the rocker box bolt extensions.

Remove the nine bolts retaining rocker box to cylinder head.

Disconnect valve lifter cable.

Tilt upward the right hand side of rocker box and extract the two long pushrods. Lay

these aside so they may be identified and replaced in their original position.

The rocker box may then be lifted off.

TO REPLACE THE ROCKER BOX

Carefully clean the top of cylinder head and lower face of rocker box.

Revolve engine until both tappets are down, i.e., the top dead centre of firing stroke.

Lay the composition jointing washer on cylinder head. This must be faultless. If

necessary, renew.

Lay the rocker box in position then slightly raise the right hand side to allow the long

push rods to be inserted into their original respective positions.

Insert all nine rocker box fixing bolts and note that the bolt with short head is in the

centre right hand position and on 500 c.c. models the bolts with threaded extensions

are fitted one each side of the central short head bolt.

Tighten each bolt in turn bit by bit until all are fully home.

On 500 c.c. models replace the engine steady stay.

Turn engine over several times to ensure parts have bedded home.

Re-fix valve lifter cable.

Re-fix rocker box oil pipe union nut using two spanners to ensure that the union

screwed into rocker box does not turn while the nut is being tightened.

Check tappet clearances and re-set if necessary.