Analysis Of Exhaust Muffler Of 4-Stroke Engine; Analysis Of Gearshift - ZONGSHEN ZS250GY-3 Service Manual

The oil in crankcase is too much.The
redundant oil should be discharged and
let the oil level not exceed the upper
mark.
[1]Check whether the elasticity of cluth spring is well-
proportioned.
[2]Check whether drive or driven hub tooth of clutch is
worn to sawtooth.
[3]Check whether friction steel pieces of clutch are
distorted.
[4]Check whether the components of operation system
of clutch are worn.
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1.6 Analysis of exhaust muffler of 4-stroke engine

The exhaust muffler of 4-stroke engine emits
blue and white thick smoke.
Check whether the oil level
of crankcase exceeds the
upper mark.
Yes
Yes
Check whether valve
and valve pipe are
worn.

1.7 Analysis of gearshift

Start engine and check whether the idle
speed of engine is too fast.
Yes
Readjust it.
Yes
Start engine.When it runs with high
speed,remove oil ruler and check whether the
oil adding hole emits smoke.
No
Check whether the match
clearance of valve and
valve pipe is too big.
No
Oil seal of valve is
damaged.
Gearshift of derailleur is
difficult.
Check whether operation of
gearshift is harmonious.
C h e c k w h e t h e r c l u t h
disengages uncompletely.
Check whether the gearshift axle is
distorted or whether gearshift arm is
distorted or worn.
No
[1]Check whether camshaf t of
gearshift or cam trough inside is
worn or damaged.
[2]Check whether the fork is worn.
[3]C h e c k w h e t h e r t h e f o r k i s
distorted.
[4]Check whether the fork axle is
distorted or worn.
No
Yes
[1]Check whether cylinder,piston
and piston ring are worn.
[2]Check whether piston ring
has poor elasticity or is dead.
[3]Check whether the opening of
piston ring has 120°to another
opening.
No
Improve operation
method.
No
Yes
Replace it