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I have a 1979 cx500 custom, and the electric start doesn't work. When I press the button to start it, the only thing that happens is the lights go dim. It will start if i bridge the terminals on the selenoid, and other than that the bike runs great. Any help would be appreciated. Thanks
 

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have you got a fully charged battery?

if you have and it's easy enough to start bridging the solenoid, then I would think the starter switch is a little corroded - spray some contact cleaner into the switch first, and with the ignition key "OFF" press the button about 10-20 times - not violently just gentle pressure - then give it another spray - see if that works - if not open up the switch and investigate further.. also spray around the OFF/RUN/OFF switch and work it through from left to right a few times- it could also be hanging up there a bit.
 

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Try disconnecting the 2 small wires on the solenoid and running them direct to the battery terminals, {polarity does not appear to be an issue} If it still doesn't crank the solenoid is at fault. These can be dismantled enough to clean the contacts or swap in another one. If it cranks trace the wires for faults or the switch may be faulty. Also are you sure that it doesn't have any safety over-ride on the starting system? Is it in nuetral? Is the neutral light on? Try pulling the clutch lever when pushing the starter button.
 

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i agree with cxphreak on this one test the solenoid
 

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In my experience lights going dim is a product of high current from the battery, so I would lean towards trouble on the big cable side of the starting system rather than a neutral or starter switch. If you have a multimeter you could watch battery voltage during cranking, and then watch the voltage drops across each component during cranking. Any component besides the starter shouldn't have more than a couple tenths volt drop across during cranking (positive cables, solenoid, ground back from starter, etc).
 

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I did a search and found this thread...

I have the same bike with the same problem.

I turn the key, the idiot lights come on, I pull in the clutch lever and push the starter button.

The headlight goes out (SOP) and the starter does NOTHING.

If I short the solenoid, the bike starts fine.

I have tried a volt meter at the solenoid and there is no current reaching it when the button is pushed.

Of the two small wires, the yellow one goes to the switch. The green/red one is a mystery to me.

I have been unable to trace it... Where does it go?



I assumed since the headlight goes out when the button is pushed, that the switch is working fine... Am I correct in thinking that?



Any wisdom sent my way will be much appreciated!
 

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light green/red goes from the neutral switch to the neutral lamp and the diode in the fuse block on the handlebars where it connects to the green/red wire via the diode. The green/red wire starts at the switched terminal of the solenoid (not the 12v+ terminal) and goes to the clutch switch and to the diode which allows only one way current flow. This ends up with two switches in parallel that can independently allow grounding of the solenoid.

The yell/red wire from the start switch connects 12v from the black wire on the start switch that comes from the ignition switch.

So, for the starter to crank you need the ignition switch to connect the battery to the black wire, the start switch to connect the black to the y/r wire, AND either the neutral switch grounding the light green/red wire OR the clutch switch grounding the green/red wire, or Both can be grounded.

Al of these various switches need to be clean with secure connections. Use a volt ohm meter and follow the circuits, look for voltage drops and corroded connections.

Whew!!
 

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Thanks guys.. Sunday is wiring day... will report back.


Well, I spent a couple hours just going over continuity.

It seems like it is all there... but NO juice at the solenoid.

I'll have to sit on this for a while and see where I'm missing something.
 
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