Assembly And Installation - Yamaha WR426F Handbuch

CYLINDER AND PISTON
2. Measure:
Piston pin-to-piston clearance
G
Measurement steps:
Measure the outside diameter (piston pin)
G
a.
If out of specification, replace the piston
pin
Outside diameter (piston pin):
WR426F: 18.991 ~ 19.000 mm
WR400F: 17.991 ~ 18.000 mm
Measure the inside diameter (piston) b.
G
Inside diameter (piston):
WR426F: 19.004 ~ 19.015 mm
WR400F: 18.004 ~ 18.015 mm
Calculate the piston pin-to-piston clear-
G
ance with the following formula.
Piston pin-to-piston clearance =
Inside diameter (piston) b –
Outside diameter (piston pin) a
If out of specification, replace the piston.
G
Piston pin-to-piston clearance:
0.004 ~ 0.024 mm
(0.00016 ~ 0.00094 in)
<Limit>: 0.07 mm (0.003 in)

ASSEMBLY AND INSTALLATION

Piston
1. Install:
Piston rings
G
Onto the piston.
NOTE:
Be sure to install the piston rings so that the
G
manufacturer's
located on the upper side of the rings.
Lubricate the piston and piston rings liberally
G
with engine oil.
4 - 47
ENG
(0.7477 ~ 0.7480 in)
(0.7083 ~ 0.7093 in)
(0.7482 ~ 0.7486 in)
(0.7088 ~ 0.7093 in)
marks or numbers are