1983 R80 G/S Gen Light

New day, new opportunity to learn.

Yesterday, when I was test riding after my first top-end reseal project, I noticed that the gen light was brighter than usual, particularly at low speeds, but eventually went off (although it was an abrupt shut-off instead of the gradual reduction of light that I'm used to when reaching higher RPMs). This morning, when I started to ride to work, the gen light started to stay on and, after a bit, wouldn't shut off at all. I got to work and don't have a volt meter, so can't check the battery for full charge, but will when I get home.

Any thoughts on where to start diagnosing a gen light that's always on? I replace the entire charging system with Rick's Omega. Based on preliminary research, might be a short somewhere or possibly a faulty rotor?

More info needed

Am I to understand you have replaced the charging system? If you did, i doubt the rotor is bad.

There is a book about charging systems for sale at http://www.motoelekt.com/goodstuff.htm

A Chilton's manual or Clymer manual can also give you pointers.

Problem could be as simple as a stuck brush to a blown voltage regulator.

Sorry I am not much better help. St.

Also

I went through and checked all the wires and they appear to be attached and clean. I forgot to mention that when I was doing the reseal, I found a stripped cylinder bolt (bottom left). This means that when I tighten the rocker arm, it doesn’t hold the exhaust valve clearance well. Any chance this is the issues instead of the actual gen light/system? In other words, would gen light come on if the valve gaps are completely wrong? Since this only started when I found the stripped cylinder bolt, I should probably assume these are all interconnected.

STEVENRANKIN said:

Am I to understand you have replaced the charging system? If you did, i doubt the rotor is bad.

There is a book about charging systems for sale at http://www.motoelekt.com/goodstuff.htm

A Chilton's manual or Clymer manual can also give you pointers.

Problem could be as simple as a stuck brush to a blown voltage regulator.

Sorry I am not much better help. St.

Click to expand...

Valves and gen light

No, the valve problem will have no influence on the charging system.

If you stripped a bolt into the engine block, that is not a good thing in its self. That is a tricky thing to fix without proper tools.

As I said, a Chilton book or the book for airhead charging systems will walk you through the check of the charging system. St.

Bolt

Yup, getting it fixed professionally tomorrow. I ordered Rick's book- hopefully that helps.

STEVENRANKIN said:

No, the valve problem will have no influence on the charging system.

If you stripped a bolt into the engine block, that is not a good thing in its self. That is a tricky thing to fix without proper tools.

As I said, a Chilton book or the book for airhead charging systems will walk you through the check of the charging system. St.

Click to expand...

Good show!

Having a troubleshooting book can save a bunch of money.

Step by step troubleshooting is cheaper than replacing parts willy nilly.

Where a-bouts are you? Who is doing the stud repair for you?

Make sure whoever does it has the proper tools for the job. Not getting it correct can make things worse. Here is a link to a site on the task. It is an older bike but basically the same deal.
https://brook.reams.me/bmw-motorcyc...-r75-5-repair-stripped-cylinder-stud-threads/

If you are in Western NY, I know a shop to get repairs and parts from. St.

Thanks

Great link- thank you.

Nope, I'm in Boston.

STEVENRANKIN said:

Having a troubleshooting book can save a bunch of money.

Step by step troubleshooting is cheaper than replacing parts willy nilly.

Where a-bouts are you? Who is doing the stud repair for you?

Make sure whoever does it has the proper tools for the job. Not getting it correct can make things worse. Here is a link to a site on the task. It is an older bike but basically the same deal.
https://brook.reams.me/bmw-motorcyc...-r75-5-repair-stripped-cylinder-stud-threads/

If you are in Western NY, I know a shop to get repairs and parts from. St.

Click to expand...

Update

Update here. It was a bad diode board. Replaced it last night and runs like a charm.

armartel said:

Great link- thank you.

Nope, I'm in Boston.

Click to expand...

Update

Thanks for letting us know what you found.

Did you get Rick's book in time to help or did you find the problem on your own? St.