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Tech Corner

Technical Q and A for classic motorcycle maintenance and repair.

Rattling 1999 BMW R1100R

Motorcycle Classics tech expert Keith Fellenstein

Editor’s note: If you’re having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith’s Garage, 1503 SW 42nd St., Topeka, KS 66609, or send an email with “Keith’s Garage” as the subject.

Rattling BMW

Q: I’m stumped. I have a 1999 BMW R1100R that sounds like it has a tin can full of swirling marbles as I go down the road and they are as loud as the engine. I rode the bike up into second, and then shifted into neutral and shut the engine off. The marbles swirled on. I have siliconed the front rotors to their mount plates which I was told was the problem. Still it sounded like marbles. Next I replaced the front wheel bearings, unhooked the speedometer cable and had the rear swingarm and wheel bearings checked. Marbles. Next I changed all oils, looking for metal of any kind with no traces. Short of pulling the transmission I don’t know what else to do. Any help would greatly be appreciated. — Steve Millard/Oregon

A: It seems you have eliminated the engine as the source of your noise, and probably the wheel bearings too, since you replaced them. Try your run up in gear again, then shut the engine off and coast, but this time apply the brakes one at a time, starting with the front. That will tell you if the pads are chattering against the disc. If that doesn’t do it, try coasting with the clutch pulled in while in different gears and listen for a change in the speed of the rattle. That would tell you if it is in the transmission. You could also put the bike on its centerstand and spin the wheels to see if the noise appears. Good luck! MC