wsm BX1800 Workshop Manual page 117

BX1800 · BX2200, WSM
Valve Lapping
1. Apply compound evenly to the valve lapping surface.
2. Insert the valve into the valve guide. Lap the valve onto its seat
with a valve flapper or screwdriver.
3. After lapping the valve, wash the compound away and apply oil,
then repeat valve lapping with oil.
4. Apply prussian blue to the contact surface to check the seated
rate. If it is less than 70 %, repeat valve lapping again.
IMPORTANT
• When valve lapping is performed, be sure to check the valve
recessing and adjust the valve clearance after assembling
the valve.
Free Length and Tilt of Valve Spring
1. Measure the free length (A) of valve spring with vernier calipers.
If the measurement is less than the allowable limit, replace it.
2. Put the valve spring on a surface plate, place a square on the
side of the valve spring.
3. Check to see if the entire side is in contact with the square.
Rotate the valve spring and measure the maximum tilt (B).
Check the entire surface of the valve spring for scratches.
If there is any defect, replace it.
[D722]
Factory spec.
Free length (A)
Allowable limit
Tilt (B) Allowable limit
[D905]
Factory spec.
Free length (A)
Allowable limit
Tilt (B) Allowable limit
1-S41
ENGINE
W10288140
31.3 to 31.8 mm
1.232 to 1.252 in.
28.4 mm
1.118 in.
1.2 mm
0.047 in.
37.0 to 37.5 mm
1.457 to 1.476 in.
36.5 mm
1.437 in.
1.0 mm
0.039 in.
W10289350
KiSC issued 07, 2006 A