Sym HD2 125 - Page 25

1. GENERAL INFORMATION
1-20
B. Engine runs sluggish (Speed does not pick up, lack of power)
Check and adjustment Fault condition Probable causes
Accelerate gradually and
check engine RPM
Engine RPM cannot be
increased
1. Replace the fuel injector
Engine RPM can be
increased
1. Clogged air cleaner
2. Poor fuel supply
3. Clogged exhaust pipe
4. Clogged fuel injector
Check ignition timing
(Using ignition lamp)
Correct ignition timing Incorrect ignition timing
1. Malfunction of ECU
2. Malfunction of AC Generator
Check cylinder compression
pressure (using compression
pressure gauge)
Normal compression pressure Abnormal compression
pressure
1. Worn out cylinder or piston ring
2. Cylinder gasket leakage
3. Sand hole in compression parts
4. Valve deterioration
5. Jammed
p
iston rin
g
Check if the fuel injector is
clogged or not
Not clogged Clogged
Remove and check the
s
p
ark
p
lu
g
Contaminated or discolored
No contamination or discoloration
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 i
g
nition timin
g
Normal Engine overheated
Check if the engine is over
heated
Continually drive in
acceleration or high speed
No knocking Knocking
1. Carbon deposit in the combustion chamber
2. Malfunction of fuel injector
3. Poor fuel quality
4. Abnormal ignition timing
To this chapter contents