BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

While working in Israel, in 2008 my gear box on my '04 R1150R collapsed, after only about 7500 miles, allegedly caused by "half-clutching". I had the gearbox rebuilt. When I picked up the bike form the Tel Aviv BMW bike dealer, it ran for 12 inches and stopped. Perplexed, what I'm assuming was a former USSR nuclear scientist, turned BMW bike mechanic couldn't figure out the problem. A week of hassling them later, they determined it was the Motronic Control Unit. Bob's BMW of Maryland and BMW American never heard of an MCU going bad on a 4 year old BMW. I argued with them to point where the TA dealer replaced the MCU free of charge, though it did take 8 weeks to get it back to me.

Fast forward to summer 2010 in New York City. Riding back home from the shore, the bike starts to do silly things, like redlining at 40 MPH while in 5th gear. I have the stick coils and spark plugs replaced and the whole works at the dealer in NYC. They break the news to me that the MCU isn't functioning correctly and that only 1 cylinder is firing. They say the reason may be due to a bent spark plug which could have been damaged or mishandled previously, causing a short. I told them that I had already had this replaced once and they couldn't believe it. The mechanic feels that the bike can be salvaged now that he's replaced the faulty spark plug. This dealer and my service manager there has been good to me, but the part would cost 1200usd plus labor.

Can I buy replace the MCU myself?

Yes, very easy once the tank is off. Buy a used one off eBay and save hundreds. Never actually heard of one ever going bad so I'm suspicious that you've had two. If they really are bad I'd suspect something else is making them that way. Alternator output voltage too high? Bad grounds? Unusual to say the least. Good luck!

Thanks John. I was also thinking about picking up a copy of the 204 R1150R repair manual and also replacing my starter, which is starting to sound squeaky.

The starter may just need some lube. I'd pull it out and check it before putting down the money to replace it. They are known to require lubricant now and then. I'd use a dry solid film lube. It won't collect dust and dry out the lube.