Classic Cycles Technical Resources
77
Connect a grounded light bulb to the hot wire of the switch. It should light if the battery is charged and the
key switch is O.K. Now connect it to the other lead from the switch. It should light when the brake pedal is
pressed. If it doesn't, the switch is bad. If it does light and the brake light doesn't work, the probable cause
lies in the bulb or in the wiring between the key switch and the bulb.
IV. HEAD LIGHT:
Connect a test bulb to the headlight wire. If, with the engine running, the bulb will not light when
connected to the head light wire, check to see if current is reaching the dimmer switch. If it is, the switch or
the wiring to the light is defective. If it does not light, check the wiring to the key switch.
Check the key switch itself by jumping the wire from the magneto lighting coil wire to the lighting hot wire.
V. HORN CIRCUIT:
Connect a light to the hot wire from the battery. If it doesn't light, check the wiring and the battery charge.
To check the horn operation, ground the horn switch wire. If you have current to the horn and it doesn't
blow, either adjust it or replace it.
VI. SELENIUM RECTIFIER:
A simple check to see if the rectifier is in good condition is to connect the leads of the continuity tester to
the terminals of the rectifier. The light should light when the leads are connected one way, but it should not
light when the leads are switched. This is because the rectifier should pass D.C. current in one direction
only. If the light lights in both connections, the rectifier is defective.
175 DT
In testing the generator and charging system, follow the procedure as listed below to locate the problem
exactly and quickly.
1. With the engine off, connect an amp meter into the circuit of the red wire on the battery at the fuse.
2. Start the engine in the day time position of the key switch and observe the amp meter. At idle, the meter
should show a discharge of 2 amps. When the engine is run faster (4000 RPM) the meter should read "0".
(No charge or discharge) with models equipped with the high-low switch and the switch is in high
charge position, the "0" (no charge or discharge) will occur at 3000 RPM.
• When the engine is run from ½ to full throttle, the amp meter should read 3 to 5 amps of charges. If all
the above tests are correct, the battery will stay charged when the cycle is operated for normal use.
3. If in the above test the 2 amp discharge was observed but no charging occurred, suspect a faulty key
switch and proceed as follows:
4. Leave the red wire from the battery to the key switch disconnected and reconnect the amp meter, one
lead to positive of the battery and the other lead to the red post of the rectifier.
5. Restart the engine and test as in #2. If readings observed in this position are correct, the key switch is
faulty and replacement is indicated. If only discharge is observed (or very low charge), 2 amp charge or
less with high-low charge switch on or 1 amp rectifier and proceed as follows:
6. Remove all wires from rectifier and connect a D.C. test light, (battery operated) one lead to the black post
and then touch the other lead to the yellow, blue, white post one at a time. Now connect the test light in
the same manner but reversing the leads, to the black post and use the opposite lead to touch the same
color terminals. In the above test, the test light should have burned at all three connections in one test,
and the test light should not have burned in the other. (D.C. current will pass through a selenium
rectifier in only one direction.) If the test light did not burn according to the above, the rectifier can be
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