Yamaha F225A Service Manual page 115

15. Remove the driven sprockets.
NOTE:
Hold the camshaft with a wrench, and be
careful not to damage the driven sprocket.
16. Remove the timing chain tensioners B,
then the camshaft caps in the order
shown in the illustration.
17. Remove the camshafts and timing
chains.
18. Remove the valve shim C from the valve
lifter D using compressed air.
NOTE:
Do not mix the valve train parts. Keep them
organized in their proper groups.
69J3D11
19. Measure the valve shim thickness with a
micrometer, and then note the measure-
ment.
20. Select the necessary valve shim by cal-
culating its thickness with the following
formula.
Necessary valve shim thickness =
Removed valve shim thickness +
Measured valve clearance – Specified
valve clearance
Example:
If the "Removed valve shim thickness" is 2.10
mm, the "Checked valve clearance" is 0.30
mm and the "Specified valve clearance" is
0.20 mm, then the "Necessary valve shim
thickness" = 2.10 + 0.30 – 0.20 = 2.20 mm
21. Install the necessary valve shim into the
valve lifter.
22. Align the projection (wide one) l on the
camshaft sprockets to the alignment
plate (gold) m on the timing chain, and
then install the camshafts to the cylinder
head with new oil seals.
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