Ground locations on 2008 Bonneville

drmuonfunk

Scooter
Hello, I'm having some electrical issues that seems to be plaguing me for the past few seasons. Last year I took a ride from NYC to Vermont. I stopped in Mass on the way home and left my light on while getting breakfast for about 30 minutes. When I tried to start her back up, I couldn't crank her over. So I pushed started the bike. Made it home but had to push start it the entire time. I finally broke down this season after replacing that older battery. I rode about 15 miles and stopped for gas. When I tried to crank it over all of the electrical went out. This was something new that I had never seen before. I decided to change the regulator and run some charging tests. The bike seems to behaving as expected. Battery sits around 12v and while idling goes up to a little over 14v. My big concern here is all the power going out. Has anyone seen this before? I checked the fuses and they are fine so I'm leaning towards an issue with the ground or bad wires. From what I can see I do not see any corroded wires. Any one have any suggestions?
 

bonZa

Street Tracker
The ground terminal is right under and at the rear of the engine connected to one of the crankcase bolts. its near where the tube for collecting crank case oil out of the airbox dangles
 

TC_Dick

TT Racer
All of the electrical going out sounds like your battery dropping out of the circuit. I just wire brushed the terminals and connectors on the battery, and that cleared up my problem with the bike randomly shutting off. Lights going out too? if not, could be one of those dumb switches?
 

drmuonfunk

Scooter
Thanks fellows. I changed the rectifier and so far it hasn't lost all power but of course I'm afraid to go more than a few miles since it left me stranded in another state last time. Here's one interesting tidbit. When I use a multimeter on the battery it reads 12volts and turn it idle it goes up to 14. But when I rev the bike it kind of goes all over the place. down to 8, 10, 14, I'm guessing that's not normal. Any one have any clue to what is going on?
 

BonnieBlack

Scooter
Did you put in a name-brand battery, YUASA or similar? I'd suspect a bad battery, but since you just replaced it seems doubtful. Unless it was a discount batteries+plus deal or something.

What kind of rectifier did you put in, another OEM one? Did the rectifier connectors in the headlight bucket look OK when you were in there? They've been known to overheat and melt down.

Battery should be over 12V fully charged with bike off, closer to 13V. 14V while idling is good, suggests the R/R is working. Sure would be nice if you could borrow a known-good battery from a buddy and see how it works. Wouldn't be the first time a bad part was replaced by another bad part.


 

drmuonfunk

Scooter
Battery I got was a US made battery but the bike killed a YUASA after a year. I think the problem has been haunting me for a few years now. I am getting that charge with off and idle. But what should I be seeing at higher revs? I'm seeing 8, 10, 14, all over the place at 5000+ RPMs.
 

BonnieBlack

Scooter
No way it should drop down to 8 and 10 ever. Bad battery or bad rectifier or bad wiring between them.

Well, the other thing you can check is that stator. Make sure you have near zero resistance between each pair of the three pins, and total resistance between each pin and the battery ground. With engine running you should get the same volts between each pair of pins. Remember it is AC on that side of the rectifier.

Or ... bad readings. If after a ride with your engine off you have near 13V on the battery then you have no problem :)
 
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