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R90/6 Starting Problem

Dave_Hemenway

New member
I have a 1974 R90/6 that ran fine yesterday, but will not start today. The Bosch starter was rebuilt by Rick at Motorrad Electric and it worked fine when I reinstalled it in the bike. I ran the bike about 40 miles with no problems. The next day I tried to start it but flooded the engine. I cleaned the dirty spark plugs and reinstalled them. The starter would not work at all. The battery is fully charged. I cleaned each of the contacts on the starter relay. The starter relay clicks when I try to start the bike, but there is no noise from the starter. The kill switch is in the proper position, the ignition lights are all working. Any suggestions would be greatly appreciated. Thanks!
 
How's the GEN light look?

Is it possible that you drained the battery in an attempt to start it (when you flooded it)? As such, is it possible that it didn't start that time because of the need for a valve adjustment?

When I've had the starter relay click, it's often been a dirty connection (in my case, it's most often been because the plug-type connector on the "front" of the starter coming off (during maintenance)).

When the starter clicks, but doesn't turn the bike over, it's the battery. "It's always the battery." Try a different battery first.
 
Starter Relay?

On my /7 when the original starter relay eventually failed after 25 years, it still clicked but wouldn't power up the starter. So don't assume your relay is OK because it is clicking. If the relay is an original, it might be time to freshen up the bike with a new one. Good luck! ;)
 
I have had a lot of similar experiences with my r90/6. I also have a rebuilt starter from Rick. Rick is good, Rick is wise.

If you're still using the original starter relay, I'd suggest getting a new one. Rick sells an awesome (cheap) alternative to the BMW part. As the previous poster said, it'll click and not do anything. Cheap insurance.

And, finally, you've got to double check the battery. Never trust that those are in working order. When I was dealing with my starter problems I totally destroyed a brand new battery. Of course, who knows how long it had been sitting on the shelf before I bought it, right?:whistle
 
Put a voltmeter across the battery terminals. Monitor the voltage as you push the starter button. If the voltage drops to low 10v or so, I'd vote the battery is bad. If the battery remains at the nominal voltage (say 12.5v), then look up stream. Starter relay would be the first thing to consider.
 
Wow, thanks for all the insightful suggestions. The red generator light is nice and bright. The battery measures 12.9 volts whether the starter switch is activated or not. So I am leaning towards replacing the starter relay, while still clicking, is propably bad. Where is the best place to get a new one? Rick, Capital Cycle, Bob's,??? Does it matter which one I get for the old girl.\?
 
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