Technical data

INSPECTION
1. Cylinder Head
Prior to washing the cylinder head, check for cracks,
damage and water leaks.
Check to see if the oil passageway feeding lube oil to
the rocker shaft is clean.
Using a straight edge and a feeler gauge, check the
lower surface of cylinder head for distortion
as shown.
2. Valve Guide
Check a valve stem to guide clearance. If the
clearance exceeds the service limit, replace the valve guide and valve.
To remove the existing guide, press it upward using
a driver from under the cylinder head.
To install a new guide, press it in to the illustrated
size using a suitable driver from above the
head.
After installing the valve guide, check the guide to
stem clearance. If the clearance is smaller
than the correct to the standard size by using
a suitable reamer.
3. Valve Seat
Check the valve seat for damage and
incorrect contact. Correct as shown
if defective. After correction, lap
the valve to the seat using a
lapping compound.
n case of excessive valve seat
sinkage over the service limit,
replace the cylinder head.
Check the valve seat sinkage by measuring
the installed length of the spring. When measuring the size up to the top of the valve
spring retainer, include retainer thickness (at the collar) of 2.0mm+/-0.25mm for the
W21 and W33 and 1.7mm+0.03,-0mm for the W27.