6-18 CYLINDER HEAD, CYLINDER AND PISTON
• Clean and assemble the head and valve components. Fill the
intake and exhaust ports with gasoline to check for leaks.
• If any leaks occur, inspect the valve seat and face for burrs or
other things that could prevent the valve from sealing.
VALVE SPRING
• Check the valve spring for proper strength by measuring its
free length and also by the force required to compress it.
• If the spring length is less than the service limit, or if the force
required to compress the spring does not fall within the range
specified, replace the spring.
Valve spring free length:
Service limit (IN.): 37.1 mm (1.46 in)
(EX.): 37.5 mm (1.48 in)
09900-20101: Vernier calipers (150 mm)
Valve spring tension:
Standard (IN.): 142 – 157 N (14.5 – 16.0 kgf)/
33.55 mm(31.9 – 35.3 lbs/1.321 in)
(EX.): 137 – 157 N (14.0 – 16.0 kgf)/
33.55 mm(30.8 – 35.3 lbs/1.321 in)
VALVE REASSEMBLY
• Install the valve spring seat.
• Apply MOLYBDENUM OIL SOLUTION to the stem seal
1
,
and press-fit it into position.
MOLYBDENUM OIL SOLUTION
• Insert the valve, with its stem coated with MOLYBDENUM
OIL SOLUTION all around and along the full stem length with-
out any break.
MOLYBDENUM OIL SOLUTION
Always use extreme caution when handling gasoline.
Replace the stem seal
1
with a new one.
When inserting the valve, take care not to damage the
lip of the stem seal.
