Honda CB350 Repair Manual page 159

154 TROUBLESHOOTING
metal object such as a nail into the plug
connectors. Using a folded cloth as insu—
lation, hold the nail about % in. from the
engine and crank the engine over with
the ignition on. If you have a fat blue
spark, remove and check the spark plugs.
If not, trace the ignition system back with
a test light used to check electrical conti—
nuity. Start by checking for electricity at
the points while they are open. If you
have juice there, the problem lies in the
coils, spark plug wires, or the wire be—
tween the coil and points. If you find that
there is no supply of electricity to the
coils, start looking for loose connectors in
the wire between the coils and ignition
switch. Speaking of connectors, when—
ever you have a problem with the elec—
trical system, they are the first things that
you should examine.
All of the above can be considered
troubleshooting the engine to get it run—
ning, not troubleshooting to cure running
faults. Once you have found the general
location of the trouble, it is usually quite
simple to make pinpoint checks or tem—
porarily substitute new parts to deter—
mine exactly where the problem lies.
The most important thing to rememberis
to try to remain rational and approach the
troubleshooting procedure logically.
Troubleshooting an engine which is
running badly is often a little bit trickier
than trying to determine why an engine
won't start. You will still be involved
with the compression, fuel system, and
electrical system of your engine, but the
problems will be more subtle and harder
to detect. It pays here, if you are making
adjustments or fine—tuning, to make one
adjustment at a time, thoroughly check
the results, and record the findings.
Otherwise, you will confuse yourself,
ruin the results of one adjustment with
another, and accomplish nothing (or
worse).
Engine Troubleshooting
Problem Possible Causes
Inspecion/Remedy
Abnormal engine noise
(top end)
inder
Excessive carbon build—up in
combustion chamber
Worn
small end
Misadjusted or worn cam chain
Worn cam or crankshaft
sprocket
Pinging or spark knock
Excessive tappet clearance
Piston knock due to worn cyl—
wrist pin or con rod
Adjust. Refer to Chapter 3.
Inspect and have cylinder bored if neces—
sary. Refer to Chapter 4.
Decarbonize. See Chapter 4.
Inspect and replace if necessary. Refer
to Chapter 4.
Adjust. Replace if adjustment does not
quiet the chain.
Inspect. Refer to Chapter 4.
Timing too advanced; See Chapter 3.
Low quality gasoline; drain and refill
tank with fresh gas.
Abnormal engine noise
(bottom end)
Rumble at idle developing into
whine at higher rpm: crank—
Inspect and replace if necessary; refer to
Chapter 4.
shaft main bearings worn or
damaged
Knock, especially noticeable at
Refer to Chapter 4.
idle, increasing with rpm: worn
con rod big end bearing
Noisy Transmission Worn gears
Worn transmission shaft splines
Inspect and replace if necessary. Refer
to Chapter 4.
Inspect; replace if necessary. Refer to
Chapter 4.