Yamaha YFM350FAS, Supplementary Service Manual

Page: 85 / 119

– 75 –
ENG
MIDDLE GEAR
SELECTING THE MIDDLE DRIVE AND
DRIVEN GEAR SHIMS
When the drive and driven gear, bearing
housing assembly and/or crankcase are
replaced, be sure to adjust the gear shims.
1.Select:
●
Middle drive gear shim
1
●
Middle driven gear shim
2
*****************************************************
Selection steps:
●
Position middle drive and driven gear by
using shims
1
and
2
with their respective
thickness calculated from information
marked on crankcase, bearing housing and
drive gear end.
1
Shim thickness “A”
2
Shim thickness “B”
●
To find shim thickness “A”, use following
formula:
Where:
a
= a numeral (usually a decimal number)
on the bearing housing is either added
to or subtracted from “4.5”.
b
= 15.0
c
= drive pinion gear to driven pinion gear
center distance (considered constant
“55”).
d
= a numeral (usually a decimal number)
on the right crankcase specifies a
thickness of “75”.
Middle drive pinion gear shim thickness:
“A” =
d
–
a
–
b
–
c