Intermittent turn signal - '93 R100R

[woodwind]

Bike is a '93 R100R with about 73k miles on it. Problem is the left turn signal - with the ignition on (and the bike not running) the turn signal functions normally, flashes until I cancel it. Start the bike up, signal works fine, and continues to be okay for the first few miles on the road. After that it will flash three or four times and then quit. Sometimes it will only flash once, other times it will flash until I hit the cancel switch.

The right turn signal operates normally under all conditions.

I just got the bike a couple weeks ago, and this is an issue the PO said he had just noticed recently.

Any ideas as to the cause?

Thanks!

[skiteach]

Could be the relay (flasher) or dirty bulb contacts or ground. I'd go for the flasher first. Many auto flashers fail in this way.

[amiles]

I would check the contacts for the bulbs and failing this being the culprit you could substitute a known good bulb in rotation in case it is the filament on one of them. A spritz of contact cleaner into the switch and all other contacts is always worth a try.

A bad ground particularly if your lights ground through their clamping/mounting hardware could be another issue. I don't recall if you indicated that front/rear or both were not functioning, if both check common items. Also check the dash indicator bulb if you have separate left and right teltales.

I don't know about your specific flasher unit, but many use the same points for both sides, which in this case would eliminate it as you report that the one side works just fine.

In some Airhead applications, when one ts bulb is not functioning the dash indicator will flash once and no more, the good bulb will be flashing all by itself. Next time you have this problem, stop as soon as safety will permit & check both front and rear bulbs, if only one is flashing, the other one is the problem, and the non flash of the dashboard light will go away when the non working one is corrected.

[skiteach]

"I don't know about your specific flasher unit, but many use the same points for both sides, which in this case would eliminate it as you report that the one side works just fine."

I have no clue as to why flashers will be intermitent on 1 side and not the other. However, I've fixed many cars that displayed these sypmtoms, by changing the flasher. The only explaination that I have is something to do with resistance. Could also be dirty fuse contacts, if they are the good old german torpedo types. Many VW's just needed fuses cleaned or rotated to get electrical gremlins sorted. Do BMW motorcycles have seperate fuses for right and left? I'm knocking on trees- never changed a fuse on my /5.

[woodwind]

Thanks, this is all good advice and will give me a direction to go in. I didn't get an owner's manual with the bike and don't know if a wiring diagram would even be in the manual, but is there anywhere I can find this on-line?

Haven't had a chance to see if either signal is actually still flashing when the indicator say's it is not, but will start with that tomorrow.

[lostboy]

The R100R uses the same turn signal relay as the late R100GS and K-bikes. These relays work by getting a brief positive signal from the switch and are cancelled by a ground from the cancel switch. Chances are that this relay has faled, since the signals on the left work briefly and the right reliably.

[jforgo]

cleaning the switch itself?

[AnnapolisAirhead]

Sounds like your switch, too much resistance in the connections and/or a faulty ground.

If you haven't found a Clymer's manual, I highly recommend one:

http://tinyurl.com/ClymersAirhead1970-1995

Cheers. :drink

[boxerr]

I had a similar problem with my GSPD, and it turned out to be a broken solder joint in the relay.
Resoldered it, and no problem since.

[The_Veg]

Could also be dirty fuse contacts, if they are the good old german torpedo types. Many VW's just needed fuses cleaned or rotated to get electrical gremlins sorted. Do BMW motorcycles have seperate fuses for right and left?

The R does not have separate left and right fuses, and it uses the modern spade-type fuses.