55
Fig.67
Fig.68
Fig.69
Fig.70
——Measure valve spring free length and spring force:
Compression
(mm)
Spring load (N)
Spring free
length
L1=37.084
422
L0=47.2
L2=27.7
892.7
L3=27.0
945
——Grinding the valve and the valve seat with the valve conical angle (Intake valve and
exhaust valve): 44
°
30
′
—45
°
30
′
Valve seat sealing width:
1.75 — 2.32mm
Installation: ——Before installation, make sure that cylinder head has been cleaned without any
grinding material on cylinder head, valve or
valve guide. ——Lubricate the valve stem and guide with clean engine oil.
——Install the valve. Notice that the intake and exhaust valve for 480 are not
interchangeable. Refer to the previous valve mark for valve assembly.
——Press the valve spring assembly with oil seal onto the top of valve guide. Apply
engine oil on the intake and exhaust valve guide edge where the valve seals are installed for preventing
valve lock piece groove from damaging oil seal lip. You may protect the valve lock groove with tape and
remove the tape after installing the valve.
——Install the valve spring and spring seat. Compress the spring seat to expose the
