N39453 Chapter 4
Page 89
How to check the valve tip clearances
The valve tip clearances are checked between the top of the valve stem and the rocker lever (AP), with
the engine cold. The correct clearance for inlet valves is 0,20 mm (0.008 in) and 0,45 mm (0.018 in) for
exhaust valves. The valve positions are shown at (AQ). Slacken the locknut and adjust the gap by turning the
adjustment screw in or out to achieve the correct gap. Re-tighten the locknut, ensuring the adjustment screw
is held from moving.
The sequence of valves from number 1 cylinder is shown in the table below.
Note: Number 1 cylinder is the furthest cylinder from the ywheel end of the engine.
1. Rotate the crankshaft in the normal direction of rotation until the inlet valve (AQ7) of number 4 cylinder
has just opened and the exhaust valve (AQ8) of the same cylinder has not closed completely. Check the
clearances of the valves (AQ1 and AQ2) of number 1 cylinder and adjust them, if necessary.
2. Set the valves (AQ3 and AQ4) of number 2 cylinder as indicated above for number 4 cylinder. Then check
/ adjust the clearances of the valves (AQ5 and AQ6) of number 3 cylinder.
3. Set the valves (AQ1 and AQ2) of number 1 cylinder. Then check / adjust the clearances of the valves
(AQ7 and AQ8) of number 4 cylinder.
4. Set the valves (AQ5 and AQ6) of number 3 cylinder. Then check / adjust the clearances of the valves
(AQ3 and AQ4) of number 2 cylinder.
Cylinder and valve number
1 2 3 4
1 2 3 4 5 6 7 8
Valve
I = Inlet
E = Exhaust
I E I E I E I E
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