Yamaha XT660R Service Manual page 95

ADJUSTING THE VALVE CLEARANCE
d
c
1
1
2
3
b
a
6. Measure:
b
• valve clearance
Out of specification → Adjust.
a
M MMM M MMM M
a. Turn the crankshaft counterclockwise.
b. When the piston is at the top dead center
(TDC) on the compression stroke, align the
"I" mark a on the A.C. magneto rotor with
the stationary pointer b on the A.C. mag-
neto cover.
NOTE:
To position the piston at top dead center (TDC)
on the compression stroke, align the "I" mark
c on the camshaft sprocket with the stationary
pointer d on the cylinder head, as shown in
the illustration.
c. Measure the valve clearance with a thick-
ness gauge 1.
Out of specification → Adjust.
L LLL L LLL L
7. Adjust:
• valve clearance
M MMM M MMM M
a. Loosen the locknut 1.
b. Insert a thickness gauge 2 between the
end of the adjusting screw and the valve tip.
c. Turn the adjusting screw 3 in direction a
or b until the specified valve clearance is
obtained.
Direction a
Direction b
3 - 14
CHK
ADJ
Valve clearance (cold)
Intake valve
0.09 ~ 0.13 mm
(0.0035 ~ 0.0051 in)
Exhaust valve
0.16 ~ 0.20 mm
(0.0063 ~ 0.0079 in)
M MMM M M MMM M M MMM M
Thickness gauge
90890-03079
L LLL L L LLL L L LLL L
M MMM M M MMM M M MMM M
Valve clearance is
increased.
Valve clearance is
decreased.
M MMM M MMM
L LLL L LLL
M MMM M MMM