ZHE JIANG KAYO MOTOR CO., LTD
www.RideKayo.com
53
For the troubleshooting of cylinder head, please refer to the following table
Description
Damage Form
Problem
Cause
Correction
Cylinder head
Too much oil dirt or sand on
the cooling fins.
Poor heat radiation of the
fins on cylinder head.
The engine overheats.
Remove the oil dirt or sand
Carbon deposit in the
combustion chamber
Overheating head
The engine overheats
Remove
the
carbon
deposit
Failure of sparking plug
threaded hole
Air leakage between the
sparking plug and
cylinder head
The engine starts hard or fails to
start
Repair the threaded hole or
replace the cylinder head
Serious deformation of
cylinder head end surface
Air leakage between the
cylinder head and
cylinder
The engine starts hard or fails to
start. Insufficient engine output;
Engine speed changes during idle
run
Grind the cylinder head
end surface or replace the
cylinder head
There are pits, ablation or
pock marks, damages on the
working surface of valve
seat.
Air leakage between the
valve and valve seat due
to improper tightness
The engine starts hard or fails to
start. Insufficient engine output;
engine speed changes during idle
run
Repair the valve seat
The inner hole of valve
guide is over worn
The
fitting
clearance
between the valve and
the valve is too large
Thick blue and white fume form
the exhaust muffler pipe
Replace the valve guide
The cylinder gasket is
broken
Air leakage between the
cylinder head and
cylinder
The engine starts hard or fails to
start. Insufficient engine output;
Engine speed changes during idle
run
Replace the cylinder head
gasket
The fixing nut is not
properly tightened
Air leakage between the
cylinder head and
cylinder
The engine starts hard or fails to
start. Insufficient engine output;
Engine speed changes during idle
run
Tighten the fixing nut
Spark plug
Improper clearance between
electrodes
Weak or no sparking
from the spark plug
electrodes
Oil leakage between the cylinder
and crankcase
Adjust electrode gap to
0.6~0.7mm
The spark plug electrodes
are joined by carbon deposit
No sparking from the
spark plug electrodes
The engine starts hard or fails to
star
Remove the carbon deposit
between the electrodes
Excessive carbon deposit or
oil dirt in the spark plug
Weak or no sparking
from the spark plug
electrodes
The engine starts hard or fails to
start. Insufficient engine output;
Engine speed changes during idle
run
Remove
the
carbon
deposit or oil dirt
The spark plug insulator is
damaged
Weak or no sparking
from the spark plug
electrodes
The engine starts hard or fails to
start. Insufficient engine output;
Engine speed changes during idle
run
Replace with a new spark
plug of the same type
The
spark plug is not
properly tightened
Air leakage between the
spark plug and cylinder
head
The engine starts hard or fails to
start. Engine speed changes during
idle run
Tighten the spark plug