Service manual

Page 39 of 151

6-2 Operation Precautions

General Information

This section contains maintenance and service information for the cylinder head, valve, and

camshaft, as well as the rocker arm.

Cylinder head service can be carried out when the engine is in the frame.

CYLINDER HEAD Specifications

Item Standard Limit

Compression pressure 170±30psi 140psi

Intake 5.90mm 5.85mm

Camshaft Height of cam lobe

Exhaust 5.70mm 5.65mm

ID of valve rocker arm 11.982~12.000mm 12.080mm

Rocker arm

OD of valve rocker arm shaft 11.966~11.984mm 11.936mm

Intake 4.975~4.990mm 4.900mm

OD of valve stem

Exhaust 4.950~4.975mm 4.900mm

ID of valve guide 5.000~5.012mm 5.030mm

Intake 0.010~0.037mm 0.080mm

Clearance between

valve stem and guide

Exhaust 0.025~0.062mm 0.100mm

Intake 38.700mm 35.200mm

Free length of valve

spring

Exhaust 40.400mm 36.900mm

Valve seat width 3.400mm 4.000mm

Intake 0.10±0.02mm or .004” -

Valve

Valve clearance

Exhaust 0.15±0.02mm or .006” -

Tilt angle of cylinder head --- 0.050

Torque Values

Bolt 7 -10 lbf-ft

Exhaust pipe stud bolt 17-22 lbf-ft

Cylinder head bolt 7 -10 lbf-ft

Cylinder head Nut 26-29 lbf-ft

Sealing bolt of cam chain auto-tensioner 6-9 lbf-ft

Bolt of cam chain auto-tensioner 9-12 lbf-ft

Cylinder side cover bolt 7 -10 lbf-ft

Cam sprocket bolt 7 -10 lbf-ft

Tappet adjustment screw nut 5-8 lbf-ft

Spark plug 7-9 lbf-ft