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Altaernator Light stays on

J

jethridge

New member
Based on the respnces received from my post about the alternator light staying on (83 R100) i have a bad Diode Board or some other problem with the charging system. My question is " Would there be damage to the system by driving some 60/70 miles to the dealer for repair? Anyone driven this far with the light on, if so any problems?
Thanks in advance for your responce
Jack Etherige
Ocala Fl
 
i drove from western pennsylvania to wooster ohio, a distance of just under 100 miles. most of that was with a solid red "gen" light. my diode board, voltage regulator and rotor were all toast. the diode board will take other things along for the scrapyard ride. i was lucky to get that far too, by the time i pulled up behind a truck at an intersection in wooster i had no lights and the bike was just barely running.
 
You'll be driving with a dead loss on the battery. If the battery is fully charged, you'll probably be OK and make it to the dealer. If not, you'd be consider an alternative or be prepared to strap an automotive battery on the back seat with cables to appropriately connect it to the dead battery. The fewer electrical items you run the better. If you could easily take the headlight out of circuit, that would be good...not sure about your bike. If you bike is naked, maybe it's easy to get inside the headlight shell and disconnect it.

Kurt in S.A.
 
BubbaZanetti said:
i drove from western pennsylvania to wooster ohio, a distance of just under 100 miles. most of that was with a solid red "gen" light. my diode board, voltage regulator and rotor were all toast. the diode board will take other things along for the scrapyard ride. i was lucky to get that far too, by the time i pulled up behind a truck at an intersection in wooster i had no lights and the bike was just barely running.
Click to expand...
Do you think that driving the 100 miles or so had anythingto do with extend of damage. All three parts going out at the same time. I have no way of knowing what has gone out or if the reg, board and and roter are shot now.
 
Hmmmm

When it happened to me I ran about 40 miles home. The bike just kept running crappier and then worse the whole time. I made it home, but if I had the choice I would have made other arrangments. Ended up getting an upgraded charging system. Another time (different bike) I overloaded the charging system and melted a diode board. Brand new battery and I made it home with no problems. (except dead diode board)
 
I drove most of the way to and all the way back from Las Vegas to Los Angeles ('bout 300 miles one way) with my alt. light on intermitantly depending on RPM's. Mostly solid on. It was due to a bad alternator... nothing else.

Be sure to test your diode board if you can. It may not be bad. At least replace the alternator before buying a diode, etc. Alternators are fairly common to replace. I'd do that first - and it's easy enough to do yourself with the removal tool. I don't think diodes go bad that commonly.

You can order a new alternator and removal tool from motorrad elektrik. The guy there (I forget his name) was super helpful and quick on shipping.

g'luck!
 

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JETHRIDGE said:
Do you think that driving the 100 miles or so had anythingto do with extend of damage. All three parts going out at the same time. I have no way of knowing what has gone out or if the reg, board and and roter are shot now.
Click to expand...


can't be 100 percent sure about any relation between the diode board and the alternator core, but i'm pretty sure the diode board would be the factor behind the toasted voltage reg............
 
The most common rotor failure is an open circuit, however since your alternator light is illuminated, the rotor isn't open.

Diode failures are normally a short circuit, with a resulting wiring and alternator stator fire. Since you didn't mention anything burned, and the bike runs normally, it is probably a failed regulator or regulator wiring failure.

If you don't want to trouble shoot it yourself, you can drive to the dealer and have them do the work for you. It would be nice if you could pull the headlight bulb connector to reduce the drain on your battery, and of course charge the battery fully before leaving.

Regards, Rod.
 
Headlight

RODSHERIDAN said:
The most common rotor failure is an open circuit, however since your alternator light is illuminated, the rotor isn't open.

Diode failures are normally a short circuit, with a resulting wiring and alternator stator fire. Since you didn't mention anything burned, and the bike runs normally, it is probably a failed regulator or regulator wiring failure.

If you don't want to trouble shoot it yourself, you can drive to the dealer and have them do the work for you. It would be nice if you could pull the headlight bulb connector to reduce the drain on your battery, and of course charge the battery fully before leaving.

Regards, Rod.
Click to expand...

The bike had a switch to turn off the dim headlight bulb when i bought it. I will turn off dim. No light unless i flick to hi beam whitch i will do with the flasher if needed to get the attention of a left turning car.
Thanks for the responce
Jack
 
alternator related question

the other day, I was a bone head, and left my ignition on for hours, and dead battery.
I fully charged the battery , 8 hours, beofre starting

now my alternator is charging higher then it used to, like above 14 but not to 16, when it used to just below 14

any ideas ?

also thanks for the motoarad electix link
 
Last edited:
Check the voltage with an accurate voltmeter. Anything above 15.5 v is not good. BMW voltmeters are not particularly accurate; just an nice to have rough indication of what's up with the charging system.
 
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