Yamaha F25A - Cylinder Head Inspection; Oil Pump Inspection; Service Points

5-21
POWR
E
OIL PUMP
SERVICE POINTS
Cylinder head inspection
1. Measure:
● Cylinder head warpage
Out of specification → Resurface or
replace the cylinder head.
Warpage limit:
0.1 mm (0.004 in)
Resurfacing steps:
● Place a 400 ~ 600 grit wet sandpaper
on the surface plate.
● Resurface the cylinder head using a
figure-eight sanding pattern.
NOTE:
To ensure an even surface, rotate the cyl-
inder head several times.
Oil pump inspection
1. Measure:
● Clearances a, b, and c
Out of specification → Replace the oil
pump.
Clearance:
a: 0.03 ~ 0.15 mm
(0.001 ~ 0.006 in)
b: 0.12 mm max. (0.005 in max.)
c: 0.08 ~ 0.03 mm
(0.003 ~ 0.001 in)