Engine; Adjusting The Valve Clearance - Yamaha YZF-R15 Service Manual

ENGINE

ADJUSTING THE VALVE CLEARANCE

The following procedure applies to all of the
valves.
NOTE:
Valve clearance adjustment should be made
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on a cold engine, at room temperature.
When the valve clearance is to be measured or
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adjusted, the piston must be at top dead center
(TDC) on the compression stroke.
1. Remove:
Front panels
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Seat
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Refer to "GENERAL CHASSIS" on page 4-1.
Fuel tank
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Refer to "FUEL TANK " on page 7-1.
2. Disconnect:
Spark plug cap
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Air induction system vacuum hose
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Air induction system hose (3-way joint to air
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cut-off valve)
Refer to "AIR INDUCTION SYSTEM" on
page 7-9.
3. Remove:
Air cut-off valve
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Reed valve
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Reed valve plate
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Refer to "AIR INDUCTION SYSTEM" on
page 7-9.
Cylinder head cover
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Cylinder head cover gasket
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Refer to "CYLINDER HEAD" on page 5-6.
4. Remove:
Timing mark accessing screw "1"
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Crankshaft end accessing screw "2"
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2
5. Measure:
Valve clearance
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Out of specification → Adjust.
s s s s s s s s s s s s s s s s s s s s s s s s
a. Turn the crankshaft counterclockwise.
b. Align the TDC mark "a" on the magnero rotor
with the stationary pointer "b" on the magneto
cover.
c. Check that the cam lobes are positioned as
shown in the illustration.
d. Measure the valve clearance with a thickness
gauge "1".
Out of specification → Adjust.
1
6. Adjust:
Valve clearance
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a. Loosen the locknut "1".
b. Insert a thickness gauge "2" between the end
of the adjusting screw and the valve tip.
3-3
Valve clearance (cold)
Intake
0.10–0.14 mm
Exhaust
0.20–0.24 mm
ENGINE
b
a
1