Yamaha MA190, Service Manual

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57
9
If the camshaft gear face damaged, please
replace the camshaft with new one.
Camshaft wearing cause analyze and to
engine performance influence:
Poor lubrication will result in camshaft
abnormal wearing, such as, oil viscosity low,
impurity too much, and recycling oil little
can’t let the camshaft surface forming com-
plete oil film to make the camshaft surface
seriously worn in the high speed rubbing
stat. Second, installing precision problem,
when the matching clearance of the cam-
shaft journal and camshaft seat or bearing
is out of the service limit, camshaft rotation
precision will lower and contacting with the
relative part produce deviation face to make
abnormal wearing.
5
Crankshaft: Push the bearing until it con-
tacts the crankshaft with care not to dam-
age the crankshaft output end and timing
gear.
9
Check timing gear for engagement clear-
ance of the chain. The camshaft, timing
chain guide, tensioner, and crankshaft tim-
ing gear should be sufficiently matched with
chain and contact governor driven gear of
the governor gear.
9
Timing gear will be damaged in gear worn,
gear face peeling off, and gear teeth broken.
Due to gear wearing, the engagement clear-
ance is bigger, the noise is bigger.
9
If the timing gear face is damaged, please
replace with new one.
TIP
Please replace the gear with a new set to
ensure the engaging face completely engage
in.
4-3 Engine
Chain guide
Driven
gear
Tensioner
Timing gear
Chain
Camshaft