Yamaha F6BMH User Manual

CAMSHAFT AND VALVES
4. Measure:
 Valve stem outside diameter
d
Out of specification  Replace.
5. Measure:
 Valve stem runout
Out of specification
 Replace.
NOTE:
When replacing the valve, always use a
new valve guide and valve stem oil seal.
CHECKING THE VALVE SPRING
1. Measure:
 Valve spring free length
a
Out of specification  Replace.
2. Measure:
 Valve spring tilt
b
Out of specification  Replace.
Valve stem outside diameter
d
:
Intake valve: 5.475 - 5.490 mm
(0.2156 - 0.2161 in)
Exhaust valve: 5.460 - 5.475 mm
(0.2150 - 0.2156 in)
Valve stem runout limit
(intake valve and exhaust valve):
0.03 mm (0.0012 in)
Valve spring free length limit
a
:
27.6 mm (1.09 in)
Valve spring tilt limit
b
:
1.0 mm (0.04 in)
5-46

Yamaha F6BMH Specifications

General

Max Output	6 hp
Starting System	Manual
Gear Ratio	2.08:1
Fuel Induction System	Carburetor
Ignition System	CDI
Lubrication	Wet Sump
Oil Injection	No
Engine Type	4-Stroke, SOHC
Weight	27 kg
Prop Shaft Horsepower	6 hp
Full Throttle RPM Range	5, 000 - 6, 000 rpm
Shaft Length	15 in
Steering	Tiller
Full Throttle Operating Range	5, 000 - 6, 000 rpm