Sym Joyride 125 Service Manual page 22

B. Engine runs sluggish (Speed does not pick up, lack of power)
Check and adjustment
Accelerate gradually and
check engine RPM
Engine RPM can be
increased
Check ignition timing
(Using ignition lamp)
Correct ignition timing
Check cylinder compression
pressure (using compression
pressure gauge)
Normal compression pressure
Check if the fuel injector is
clogged or not
Not clogged
Remove and check the
spark plug
No contamination or discoloration
Check if the engine is over
heated
Normal
Continually drive in
acceleration or high speed
No knocking
To this chapter contents
1. GENERAL INFORMATION
Fault condition
Engine RPM cannot be
increased
Incorrect ignition timing
Abnormal compression
pressure
Clogged
Contaminated or discolored
Engine overheated
Knocking
Probable causes
1. Clogged air cleaner
2. Poor fuel supply
3. Clogged exhaust pipe
4. Clogged fuel injector
1. Malfunction of ECU
2. Malfunction of AC Generator
1. Worn out cylinder or piston ring
2. Cylinder gasket leakage
3. Sand hole in compression parts
4. Valve deterioration
5. Jammed piston ring
1. Replace the fuel injector
1. Remove the dirt
2. Incorrect spark plug heat range
1. Worn out piston or cylinder
2. Abnormal fuel injector
3. Poor fuel quality
4. Carbon deposit in the combustion chamber
5. Abnormal ignition timing
1. Carbon deposit in the combustion chamber
2. Malfunction of fuel injector
3. Poor fuel quality
4. Abnormal ignition timing
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