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Bike wont stay running with lights on... Need help

2610 Views 8 Replies 6 Participants Last post by  patd88
Hi everyone,

I Have a custom ridged chopper with a harley EVO 88ci engine in it, Bare necessities just a head light and rear brake light, No speed O, or turn signals.

So to get to the problem I rode my bike to work in the morning and home from work with no issues. When i got home i did not realize that i left my ignition on until i wanted to go out about five hours later. Went to start it bike was totally dead no cranking or nothing. So i decided to just jump it off my car started right up let it sit there for a minute and took off got about 100yrds and the bike died. Walked the bike back jumped it again. I came to realize that with the lights off it would start and run fine. Went for a ride to charge the battery. Battery charged but still would not run with lights on this is my problem.
Also a little FYI I put the battery on a tender and it is charged now continues to start the bike fine but just will not stay running when lights are on. Any help will be appreciated. Thanks in advanced
1 - 9 of 9 Posts
Could you possibly have a shorted wire in the head light or switch that kills the bike or a loose cable to the battery?
Also check current draw on battery as well as bat voltage charged than turn on key and see how far the voltage drops may be a bad batt.
Have the battery load tested.
My guess, you need to replace the battery. If you are near a dealer you could have the dealer check to see if you have a dead cell or if the battery needs replacement.

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Thanks guys for all the help I tested the battery with a multi-meter it read 12.50 V sitting and 12.34V with ignition turned on with lights on. I don't know if I'm right but the battery can still be bad and have good voltage right? Also I read something about the Voltage regulator may have blown due to trying to over charging the bike when i first jumped it with a dead battery. Anyone have info on that? Thanks again to all.
How many volts with bike running?
A fully charged battery will measure 12.8v or more static and 13.5v or more with the engine running.
Yes, jumping the battery can fry the regulator. If the volts measure 13.5v or more with the engine running the regulator is most likely ok. If the battery drains with the ignition off after sitting a while a diode inside the regulator burnt out.
Take the battery to an auto parts store and have it load tested, make sure it is fully charged first.

Thanks guys again for all the help. Just ended up being a wire grounded out just had to trace all the wires and figure it out. But thanks to you all I was able to narrow it down. Thanks again
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