No generator light

[dwerbil]

Just happened the other day on the the R100/7 (125k miles). As I was commuting to work the other morning, the generator light came on bright while at highway speed. Being just a few miles from home, I turned around. The generator light would go on and off a bit then stay off for a few minutes while riding home.

I noticed it was off for some time, and just for curiosity's sake, to check if the light still worked, I pulled in the clutch to let the engine drop down to idle while at speed. The gen light came on like usual, but it then stayed on the last few miles back home.

After parking the bike in the garage, I started the bike -- no generator light now. Pulled the front cover, everything looks intact. Tried a different regulator to no avail. Suptin' failed.

A couple months ago, I replaced alt. brushes and installed a new diode board. No issues since then until now.

[SteveD]

Check that the 3 wires coming off the alternator to the Diode Board haven't lost insulation coming out from behind the ignition timing cover. They might be to earth.

Were the brushes wound on enough?

[Bamboo812]

First thing to check when no light is continuity at the slip rings. Use a penny to short across the rings, if the light comes on your rotor is shot.

[Major Softie]

First thing to check when no light is continuity at the slip rings. Use a penny to short across the rings, if the light comes on your rotor is shot.

I thought the first thing to check when no light was the light.

[Bamboo812]

First thing to check when no light is continuity at the slip rings. Use a penny to short across the rings, if the light comes on your rotor is shot.

I thought the first thing to check when no light was the light.

That's what I'd check next, if the light didn't come on... Way easier to do the penny thing than remove and tear an instrument cluster apart.

[dwerbil]

The penny test causes gen idiot light to come on, so that's a bad rotor, as you say. Suppose if I were adventurous enough, I could rewind it myself. But think I'll spring for another one.

[dwerbil]

Any ideas about this rotor? Seems like a good price.....

http://www.euromotoelectrics.com/produc ... tor642.htm

Other than cost, I wonder what the difference is with this one...

http://www.euromotoelectrics.com/produc ... r642oe.htm

[Kurt in S.A.]

While not a perfect test, what does the resistance read across the rotor slip rings? Should be about 7ohms. Sometimes the windings don't separate until they are under operation. Rick at Motorrad Elektrik rewinds rotors...he keeps yours and sells you a rewound one.

http://www.motoelekt.com/charging.htm

Kurt in S.A.

[Bamboo812]

Either way, make sure you have the correct tool to pull it. Also sold on those websites.

[dwerbil]

While not a perfect test, what does the resistance read across the rotor slip rings? Should be about 7ohms. Sometimes the windings don't separate until they are under operation. Rick at Motorrad Elektrik rewinds rotors...he keeps yours and sells you a rewound one.

http://www.motoelekt.com/charging.htm

Kurt in S.A.

Kurt, it read 0 ohms.