I had never noticed it before.
The battery light is on (but very dimly; there's no way to notice it in daylight). It gets brighter (but still dimmer than when it's supppsed to be on) when the brakes are applied or the turn signals used.

The bike recently got a new battery; could that be related?

IS the dim battery light a problem (it turns on nice and bright with the ignition on and the engine off)?
How do I go about diagnosing/fixing it?

Don't worry about it, it's a common thing with early Ks. Just to be sure that it is charging properly connect a multimeter set to 20 volt range across the battery. Start the bike and rev to 2500 rpm. Battery voltage should be around 14 volts.

aye avenger ....same with me

Sometimes new brushes and a clean of the commutator can stop it but if it is charging let the sleeping dog lie.

mine does that also. BMW issued a service bulletin to fix it which involved fitting a diaode. But the charging system works fine even with the light on dimly. Don't worry about it.

If ya really want to fix it...

Installation of Diode:
Diode--part no. 61 31 1 358 268--can be installed near the alternator.
Cut the blue wire approximately 2 inches from the plug-in connection at
the alternator and splice in the diode. The diode and splice connections
must be protected from elements with heat-shrink tubing or electrical tape.
OR The diode can be spliced into the blue wire inside the electrical
equipment box under the rear of the fuel tank.

Direction of Diode:


The arrow on the diode must face towards the alternator.

Nah,............ don't worry 'bout it, mine did that too. Check the charge voltage (engine above 1500 rpm), if she's around 14v go for a ride, get a smile on ya dial, then come back and have a stubby. Never aproblem with my olk RT, could leave her for 4 weeks in winter and she'd start easy. Only ever left her idle for that long once, and only because I was away. My rule - must ride the old girl at least once a week.

agree there dennis ....its a fantasic feeling to swing the leg over at the end of a hard week ....and go for a cruise





or you can go down to the local jaycar or other electronics outlet and buy a in5404 diode for about 30 cents blakey

Thanks Charlie, I'll keep that in mind.