CHK
ADJ
ADJUSTING THE VALVE CLEARANCE
6. Measure:
•
valve clearance
Out of specification
-->
Adjust.
a. Turn the crankshaft counterclockwise.
b. When piston #1 is at TDC on the compression
stroke, align the TDC mark
a
on the AC
magneto with the mark
b
on the crankcase
cover.
c. Measure the valve clearance with a thickness
gauge
1
.
Out of specification
-->
Adjust.
7. Adjust:
•
valve clearance
a. Loosen the locknut
1
.
b. Insert the thickness gauge between the
adjustment screw end and the valve rod tip.
c. Turn the adjustment screw
3
with a wrench
2
in one of the following directions to obtain the ideal
clearance.
To place the piston at the Upper Dead Center
(UDC) on the compression time, match the "I" mark
c
of the sprocket camshaft with the mark
d
at
the cylinder head, as shown in the illustration.
NOTE:
T TT
T TT
T TT
T TT
T TT
T TT
T TT
T TT
T TT
T T
T
T
T TT
T TT
T
T
T
T
TTTTTTTTTTTTTTTTTTTTTTTTTTTTT
T
T
TTTTTT
T
T
T
T
TTTTTTTTTTTTTTTTTTTTTTTTTTTTT
T
T
TTTTTT
T
T
T
T
Clockwise
The clearance is increased
3-8
The clearance is decreased
Counter-
clockwise
a
b
d
c
1
2
3
Adjustment screw wrench
90890-01311
Thickness gauge
90890-03079
Valve clearance (cold)
Intake valve
0.05 ~ 0.10mm (0.002 ~ 0.004 in)
Exhaust valve
0.08 ~ 0.13mm (0.003 ~ 0.005 in)
Summary of Contents for YBR250 2007
Page 1: ...YBR250 SERVICE MANUAL 5D1 F8197 E0 2007 ...
Page 2: ......
Page 359: ...YAMAHA MOTOR DA AMAZÔNIA LTDA ...
