Spark Test - Honda Motorcycle Service Manual

IGNITION SYSTEMS
The sampling time of the multimeter (display switch-over
time) is approximately 0.4 second. This amount of time may
be almost similar to period of the pulses when cranking with
a kickstarter.
Under this condition, because of the multimeter sampling
time and the capacitor discharge timing, the peak voltage
reading of the multimeter may be t o low.
In case of t h e sampling t i m e ( A ) s h o w n i n the figure,
multimeter indicatesa high peakvoltage, and in case of (B), it
indicates a l o w one. For this reason, measure the peak
voltage several times i n order t o ensure a correct peak
voltage reading.
SPARK TEST
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Remove the spark plugs from the cylinder head and reconnect
them t o the plug caps.
Ground the spark plug to the cylinder head and turn the
ignition ON. Avoid h o l d i n g t h e spark p l u g t o prevent
electrical shock. Check if a good spark occurs while cranking
the engine with the starter.
A high voltage spark will appear at the spark plug gap.
For multi-cylinder engines, remove the spark plug from each
cylinder.
For some models with theCDI svstem. there is a circuitwithin
the ignition control module designedto turn off the spark at
low cranking speeds (below 200
-
500 rpm). In this case,
leave the spark plug i n the cylinder head and try the spark
test with a known good spark plug.
Some ignition control module are designed to turn off the
spark when the transmission is in gear or reverse position.
If the plug fires, the spark plug is good
Note that spark plugs are more difficult t o fire in dense air than
under normal atmospheric conditions. Thus, even though a
spark occurs under normal conditions, it may not occur in the
compressed cylinder environment.
For this reason, you should check that the secondary coil has
sufficient voltage by following the procadure that follows:
Attach a spark plug adaptor. Ground the black wire to the
engine and conduct the spark plug test.
If there ia a spark across the gap in the adaptor, the ignition
coil is good.
TOOL:
SPARK ADAPTOR 07GGK-0010100
(Except USA)
If a spark occurs across the spark plug gap, but no spark
occurs with the adaptor on, the secondary coil voltage is
insufficient.
SPARK ADAPTOR
Date of Issue: March, 1995
o
HONDA MOTOR CO..LTD.
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