wsm STW37 Workshop Manual page 143

STW34, STW37, STW40, WSM
Valve Recessing
1. Clean the cylinder head surface, valve face and valve seat.
2. Insert the valve into the valve guide.
3. Measure the valve recessing with a depth gauge.
4. If the measurement exceeds the allowable limit, replace the
valve.
5. If it still exceeds the allowable limit after replacing the valve,
replace the cylinder head.
Factory specification
Valve recessing
Allowable limit
(1) Cylinder Head Surface
Clearance between Valve Stem and Valve Guide
1. Remove carbon from the valve guide section.
2. Measure the valve stem O.D. with an outside micrometer.
3. Measure the valve guide I.D. with a small hole gauge, and
calculate the clearance.
4. If the clearance exceeds the allowable limit, replace the valves.
If it still exceeds the allowable limit, replace the valve guide.
Factory specification
Clearance between
valve stem and valve
guide
Allowable limit
Valve stem O.D. Factory specification
Valve guide I.D. Factory specification
1-S64
ENGINE
0.05 (protrusion) to
0.15 (recessing) mm
0.0020 (protrusion) to
0.0059 (recessing) in.
0.40 (recessing) mm
0.0157 (recessing) in.
(A) Recessing
(B) Protrusion
9Y1211109ENS0094US0
0.040 to 0.070 mm
0.00157 to 0.00276 in.
0.10 mm
0.0039 in.
7.960 to 7.975 mm
0.3134 to 0.3139 in.
8.015 to 8.030 mm
0.3156 to 0.3161 in.
9Y1211109ENS0095US0
KiSC issued 11, 2014 A