R80G/S Starter randomly engaging
 

Hi Folks,
My '81 R80G/S is experiencing a peculiar problem - the starter solenoid is being activated at random times while the bike us running, and once it even kept trying to start even after I hit the kill switch and turned the ignition key off. Unplugging the lead to the solenoid stops the starter from engaging, so the starter itself can be ruled out.

After studying a wire diagram of the bike, my first guess would be that the starter relay is perhaps faulty. Is this a possibility?

I've been blessed with not a single electrical problem on any of my bikes ever, so diagnosing this is going to take me a while. I should note that I did check the starter button itself to make sure it wasn't engaging, and it seems to be fine, I can't possibly imagine how that could be the problem.

Thanks,
Wright

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Wright Bagwell
http://www.geocities.com/wwbagwell/

Hi Wright,

Let us assume it is the starter relay, so we'll test it. Connect a DMM to the lead that goes to the starter solenoid (disconnect the lead from the solenoid). Turn on the ignition switch and hopefully the DMM will indicate 0V until you press the starter button, at which point it should indicate roughly 12 V.

Next, with the DMM conected to the lead that connects to the starter solenoid (starter solenoid still diisconnected) and the starter button NOT pressed, tap the starter relay with the handle of a screw driver and see if the DMM indicates any voltage. If it does, the return spring is weak and maybe the internals of the relay are sticking as well.

Let us know how you make out.

Are you sure the starter button on the right handlebar switch is serviceable.

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Alex

Alex's BMW Motorcycle & Global Touring Page http://www.ott.igs.net/~ace

Hi Alex,
Thanks for the info. It turns out it was the starter relay. Good thing I didn't have to start checking each individual wire for shorts.

After fixing that I realized that most of the other relays in the bike are bad as well. I'm hoping there isn't a more serious issue that's caused all these things to go bad.

Oh, and as for the starter button being servicable... well, when I took it apart the little bearing that's held by a spring on the kill switch that holds it in place did fly about 50 feet when I opened it... a design that as you say, isn't nicely servicable. Oh well. This has been a good learning experience though.

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Wright Bagwell
http://www.geocities.com/wwbagwell/