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CYLINDER HEADIV ALVE/CAMSHAFT
TROUBLESHOOTING
•
Engine
top-end
problems usually affect engine performance
.
These
can be diagnosed by a
compression
test,
or by trac-
ing top-end noise with a sounding rod or stethoscope.
•
If the performance is poor at low speeds, check for
a
white smoke
in
the
crankcase breather hose. If
t
he hose is smoky,
check for seized piston ring
(page
10-2),
Compression too
low,
hard
starting
or poor performance
at low speed
•
Valves:
-
Incorrect valve adjustment
-
Burned
or bent valve
-
Incorrect valve timing
- Broken valve spring
-
Uneven valve seating
-
Valve stuck open
•
Cylinder head:
- Leaking or damaged cylinder head gasket
- Loose spark
plug
-
Wa rped or cracked cylinder head
•
Cylinder/piston problem (page 10-3)
Compression too
high,
overheating
o
r
knocking
•
Excessive carbon build-up
on
piston head or combustion chambe
r
•
Worn or damaged decompressor system
Excessive
smoke
•
Worn valve stem or valve guide
•
Damaged stem seal
•
Cylinder/piston problem (page 10-3)
Excessive noise
•
Incorrect valve clearance
•
Sticking valve or broken valve spring
•
ExceSSively worn valve seat
•
Worn or damaged camshaft
•
Worn rocker arm and/o
r
shaft
•
Worn rocker arm fo
l lower
or valve stem end
•
Worn or damaged push rod
andlor
cam
follower
•
Worn cam chain
•
Worn or damaged cam chain tensioner
•
Worn cam sprocket
teeth
•
Cylinder/piston problem
(pa
ge
10-3)
Rough idle
•
Low cylinder compression
9-5
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Table of Contents
Troubleshooting
