163 09/02
Problem
1
2
3
The engine speed up
The engine does not
speed up
Check the ignition timing
(using an adequate light)
4
5
6
Correct timing
Incorrect timing
1
2
1
Correct
Incorrect
2
1
Normal compression
Irregular compression
Check that the carburator is
not clogged.
2
3
4
5
Not clogged
Clogged
1
Remove and check the spark
plug
The plug is not encrusted
nor discoloured
Encrusted or discoloured
spark plug
1
2
Correct and not
contaminated
Incorrect and
contaminated
1
2
3
Correct lubrication of the
timig system
Incorrect lubrication of
the timing system
1
2
The engine does not
overheat
The engine overheats
1
2
3
4
5
6
7
8
Speed up rapidly or let the
engine run at a high speed
Remove and check the
cylinder head oil plug
Remove the oil dipstick and
check oil level and condition
Cylinder compression inspection
Check valve clearance
Check the engine for
overheating
Start the engine and speed up
slowly
Possible cause
Check/adjustment
NO ENGINE POWER
Clogged air cleaner.
Clogged fuel gallery.
Fuel gallery clogged between the tank and
the carburator.
Clogged exhaust pipe.
Defective automatic starter.
Broken vacuum piston diaphragm.
Defective CDI unit.
Defective A.C. generator.
Incorrect valve clearance adjustment.
Worn valve seat (the valve pin is too
projecting).
Incorrect valve running along
the seat.
Worn compression rings and cylinders.
Burnt cylinder head gasket.
Cylinder head failure.
Incorrect valve timing.
Clogged carburator jets.
Encrusted plug.
Incorrect heat rating.
High oil level.
Low oil level.
Oil change not carried out.
Clogged oil pipe.
Defective oil pump.
Insufficient coolant.
Defective thermostat.
Worn cylinder and compression ring.
Lean mixture.
Low fuel quality.
Excess of carbon.
Advance ignition timing.
Air in the cooling system.
Excess of carbon in the combustion
chamber.
Low fuel quality.
Clutch slippage.
Lean mixture.
1
2
3
4
The engine knocks
The engine does not
knock
