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Honda Shadow 750 1999 battery problem

Posted: Mon Jul 07, 2014 8:09 am
by Kuurus
Hi everyone !

My friend's motorcycle is in the garage shop, for a electrical/battery problem.

Bike is a Honda Shadow Classic 1999 750cc

I am asking you this question because since the first shop couldn't find the problem, maybe one of you guys did see this before.

Here is the story:

Last year, my friend's battery was dead when she tried to start the bike. Happened out of nowhere, no signs or anything.
She changed the battery.

This year, we take the bike out of the storage, we start the bike, everything runs fine... We do a couple runs together, no problem whatsoever. About 3 weeks ago, on a longer trip in the back roads of Quebec, her battery starts smelling like rotten eggs and the seat above it turns burning hot... She stops the bike, waits for 30 minutes... And the bike won't start, no light, no indicator, nothing: battery seems dead. She gets towed to the nearing shop, (about 1.5 hr later) and she decides to try the bike... And it starts again !

So she goes home staight, and when she arrives, the bike smells again of rotten eggs, and battery runs hot.

She takes the bike to a repair shop, they test the charging system and says everything is ok, billing her 200$ for time and new battery.

This week-end, we drive from Quebec to Burlington, about 500km on saturday, and proceed to come back on sunday... On the come back trip, we smell of a slight sent of rotten eggs... And continue our way. About 3-4 hrs later, her whole bike lights turns crazy, like a christmas tree, and then everything turns off. She stops on the road side, smelling of rotten eggs, a high pitched sound (like a high pressure gas leaking) and battery burning hot again... This time the bike was dead.

Soooooo... Have anyone seen this problem and/or know the solution ? She wants to do longer rides than staying in a 30min radius, and also not have to be towed a 3rd time !

I'll update the thread if the solution is found before getting it here.

Thanks for everyone's help !

Re: Honda Shadow 750 1999 battery problem

Posted: Mon Jul 07, 2014 4:25 pm
by pchast
Check all the wiring looking for a short to the frame where
a wire is rubbed bare.

Re: Honda Shadow 750 1999 battery problem

Posted: Mon Jul 07, 2014 4:46 pm
by Johnj
Sounds like the battery is being overcharged

Re: Honda Shadow 750 1999 battery problem

Posted: Tue Jul 08, 2014 4:43 am
by Kuurus
Fried voltage regulator...

I hardly understand why the first mechanic did not see this on the first tests but it's going to be fixed this time !

Re: Honda Shadow 750 1999 battery problem

Posted: Tue Jul 08, 2014 12:35 pm
by BRUMBEAR
sorry I just saw this overcharging would have been my guess as well.

Re: Honda Shadow 750 1999 battery problem

Posted: Mon Jul 14, 2014 3:13 am
by Kuurus
It also fried almost every lightbulb when it died :P