Tappet clearance (fig. 2)
Every 3000 km (2000 miles) or any time valve operation is too noisy, tappet clearance should be checked.
This adjustment is made on a cold engine with the piston at TDC exactly at the end of its compression stroke.
After removing the cylinder head cover, operate as follows:
On a new engine, this adjustment must be made after the first 500 km (300 miles).
slacken nut 'A';
screw in or out the adjuster screw 'B' until the following clearances are obtained:
- inlet valve mm 0,22 (750, 850, 1000) and mm 0,15 (V35, V50, V65).
- exhaust valve mm 0,22 (750, 850, 1000) and mm 0,20 (V35, V50, V65).
Use a feeler gauge 'C' to check this clearance. When this is excessive, there will be noisy valve operation:
if it is less, the valves may not close fully causing inconveniences such as:
- compression loss;
- engine overheating, etc.