Yamaha FZ 25 2021 - Engine Checks and Adjustments; Adjusting Valve Clearance

3-4
CHK
ADJ
ENGINE
ENGINE
ADJUSTING THE VALVE CLEARANCE
The following procedure applies to all of the
valves.
TIP
o Valve cleara nce adjustment should be made on a cold eng ine, at room tem perature.
● Valve clearance adjustment should be made
on a cold engine, at room temperature.
● When the valve clearance is to be mea-
sured or adjusted, the piston must be at top
dead center (TDC)
on the compression
stroke.
1. Remove:
•
Fuel tank right side and left side panels
Refer to “FUEL TANK” on page 6- 1 of
base service manual B97-F8197-E0.
2. Disconnect:
• Cylinder head breather hose “1”
• Canister hose from fuel tank “2”
• Spark plug cap “3”
3. Remove:
• Oil cooler 
Refer to “OIL COOLER” on page 5-
48 of
base serv
ice manual B97-F8197-E0.
• Cylinder head valve covers along with “O”
ri
ngs
Refer to “CYLINDER HEAD” on page 5-6
of bas
e service manual B97-F8197-E0.
4. Remove:
• Timing mark accessing screw “1”
• Crankshaft end accessing screw “2”
5. Measure:
• Valve clearance
Out of specification  Adjust.
a.Turn the crankshaft counterclockwise.
b.Align the “I” mark “a” on the AC Magn
eto
rotor
with the stationary pointer “b” on the
AC Magneto cover.
c.Check that the cam lobes are positioned
as shown in
the illustration.
TIP
At this position, both the valves must have
some valve clearance.
d.Measure the valve clearance with a feeler
gauge “1”.

Out of specification  Adjust.
Center plug spanner
YSST-625
Valve clearance (cold)
Intake
0.05-0.10 mm
Exhaust
0.08-0.13 mm
Feeler gauge
YSST-1215 (90890-03180)
B9X-F8197-E0.book Page 4 Thursday, July 16, 2020 2:28 PM