Generic Onyx 50, Service Manual

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Diagnosis on power shortage of engine
Power shortage of engine
Raise the main kickstand and lift wheels; rotate
wheels with hands
Flexible rotating
of wheels Inflexible rotating of
wheels
Check tyre
pressure 1. Check whether there is
braking drag.
2. Check whether wheel bearing
is excessively abraded or
damaged.
3. Check whether the spacer
sleeve of hub is missed or too
short.
Low pressure Normal
pressure
Check whether air leakage
occurs to tyre valve and whether
tyre is pierced or broken Remove the spark plug and block the threaded
hole with finger; press the startup button or
step on the kick-start lever
Touch with your fingers and you can
feel fierce air rushing out with puffing
sound. Touch with your fingers and you can not
feel fierce air rushing out.
Normal compression
pressure of cylinder
Insufficient compression
pressure of cylinder
1. Check whether there is air
leakage in all outer joints of
engine.
2. Check whether air supply is
timely conducted.
3. Check whether clearing
between valves is too small.
4. Check whether valve and valve
seat are well sealed.
5. Check whether piston ring is
ruptured, blocked in the groove
or lacks elasticity.
6. Check the abrasion of piston
ring and cylinder.
Start the engine and slow accelerate;
observe the rotation speed change of
engine.
The rotation speed of engine rises as it
slowly accelerates. The rotation speed of engine does not rise
as it slowly accelerates.
Check whether ignition is timely
conducted with an ignition timing
light 1. Check whether the clutch is slipping.
2. Check whether the driving belt is
excessively abraded.
3. Check whether the centrifugal roller of
driving pulley is excessively abraded.
4. Check whether the conical surface of
driving wheels and friction wheels is
excessively abraded or abraded as
groove.
5. Check whether the conical surface of
driven wheels and moving driven wheels
is excessively abraded or abraded as
groove.
6. Check whether the roll-away nest on the
inner surface of friction wheels is
excessively abraded or pressed into be
concave.
1. Check whether the fuel supply system
works normally.
2. Check whether the carburetor, air filter
and exhaust muffler are blocked.
3. Check whether the vacuum diaphragm
of plunger valve of carburetor is
cracked or broken.
4. Check whether the height of
carburetor float is proper.
1. Check whether CDI
ignition device is in
good condition
2. Check whether
flywheels and trigger
coil are loosened