Specifications

Chapter 1 Engine, clutch and gearbox

spark plug lead, the exhaust pipe and the cylinder head steady

bolt, as described in Section 5 of this Chapter.

2 Slacken and remove the three rocker cover mounting bolts,

and lift the cover away, taking care not to damage the rubber

sealing

ring.

The rocker arms may be removed as a unit together

with their common support bracket. This is retained by a single

bolt at each end, and a central bolt. Lift out the pushrods and

push them through holes in a piece of card which has been

marked to denote inlet and exhaust. Although the pushrods are

identical, it is preferable to replace them in their original posi-

tions.

3 The cylinder head is retained by four large sleeve bolts, one

of which is recessed into the large diameter oil passage. An

additional special bolt passes down into the end of the cam

follower shaft, and this should also be removed. Note that the

pushrod guide bracket will be released as the two left-hand

cylinder head sleeve bolts are removed. The cylinder head can

now be lifted away and placed to one side to await further

attention. Make a note of the position and sizes of the dowels

fitted over three of the four studs. One of these is fitted with an

0 ring and acts as an oil feed passage.

4 The cylinder barrel is retained by two bolts passing through

a flange on the left-hand side. Once these have been removed,

the barrel can be slid upwards off its mounting studs. As soon

as the bottom of the barrel is clear of the crankcase mouth, the

latter should be packed with clean rag to obviate any risk of

pieces of broken piston ring or other foreign matter falling into

the crankcase. Be careful not to twist the barrel as it is removed,

or the cam follower feet may be scratched on the sharp cam

gear teeth.

5 Use a pair of pointed nose pliers or a small screwdriver to

dislodge the circlips, which should then be discarded. Note that

new circlips should always be fitted in view of the risk of a

displaced circlip causing engine damage. If the gudgeon pin

should prove to be a particularly tight fit, the piston should be

warmed first, to expand the alloy and release the grip on the

steel pin. If it is necessary to tap the gudgeon pin out of posi-

tion, make sure that the connecting rod is supported to prevent

distortion. On no account use excess force.

Fig.

1.1

Sectional view of engine/gearbox unit showing component location and lubrication system