finding electrical short (motorcycle)?

My chopper is dead again. It konked out when I got caught in a rainstorm. It died and I lost all power including lights. This has the most basic of electrical systems and no guages, etc.

I checked and charged the battery -- AOK.

The main 30A fuse of the battery was blown, so I replaced that. When I turn the ignition key, I get no response (lights should come on) and the fuse blows again. I assume this means I have a short.

I saw no obivous breaks, frays, disconnections or damage along the wires. How do I go about finding this ellusive short?


-don

 

I'm not a bike mechanic, but are their any junction boxes, relays, etc that could have filled with water? Since it died in a rainstorm, I'd look there..

 

check your grounds. see if your getting power to the switch and out of it. you say it got wet. might be corrosion in the switch it self. might be the wire in the headlight shorted out from the moisture. just start checking for power everywhere. check everything don't just awesome it looks ok.

 

try disconecting the key switch and testing each lead (ignition,lights,genorator,) off it one at a time. when you dont blow the fuse that one is good

 

Update:

I checked again and found that the *moment* that I install the main fuse and connect it, I can hear sizzling back at the regulator, which is mounted out low behind the engine. If I leave it connected for more than a second, the fuse fries. So it has to be the regulator. I'll pull it out and check.

Thanks,
don

 

If your ign and light switches are on the bars or the lamp, remember that the greased steering head bearings are not good conductors. Run a heavy ground wire discreetly from the lamp shell to the frame, to bypass the bearings.
Also maybe your regulator box needs to be sealed against the wet and grit, etc?

 

Bad grounds don't usually blow fuses. But they do cause all kinds of other problems. I wired a Bonneville about 25 years ago so I gotta admit I don't know shit about bike wiring but I do know car electrical sysytems and the same technique should work. I'd disconnect and temporarily insulate everything you can and thow in a fuse. If it does'nt blow then you methodically reconnect one system at a time untill you do find the problem. Another troubleshooting idea is to disconnect one battery cable and install a small seat belt buzzer in series (in between the cable you disconnected and the battery post it was on). If there's any draw the horn will buzz. Start disconnecting stuff one piece at a time untill the buzzer stops. The big advantage here is the buzzer is so frgg'n annoying you want to work faster (LOL)

 

[ QUOTE ]
If your ign and light switches are on the bars or the lamp, remember that the greased steering head bearings are not good conductors. Run a heavy ground wire discreetly from the lamp shell to the frame, to bypass the bearings.
Also maybe your regulator box needs to be sealed against the wet and grit, etc?

[/ QUOTE ]

The switches are on the electrical box, in the frame.

The regulator is exposed and that could have lead to the problem. It bolts to the rear fender and sits behind the engine. It needs airflow to keep cool but perhaps the rain caused some damage.

I'll pull it out tomorrow to have a closer look.

Thanks for all the advice.

 

I won a Yamaha 250 Enduro in a "friendly" nickle and dime 21 game that was a cheap bet becaus eit "just qiut running one day" The Magneto was half full of water... That's all. Drained it, a little poouff with a hair drier and WD 40 and it was back on the road!