Front brake pulsing and grabbing! Found out why.

[KB13]

Hello everyone:
Bought a 2003 R1150R (non ABS brakes) a couple of months ago. Loved the bike but the front brake lever would pulse and the brake grab so I didn't even want to use it. Tried most of the things I found here on the board, put on a new front tire, new brake shoes, cleaned everything, etc. - no change. Took it to the dealer. They said it had warped disks. They had to order them so I took it home while waiting. I decided to check myself and used a dial gage but the disks seemed to be perfectly flat. I took them off and had a local brake/machine shop check them and they very lightly machined both disks but said they were perfectly flat and true. Put the rotors back on and it still had the same problem. Checked the rim with the dial gage and it was bent about 1/8th of an inch (this was at the outside edge of the rim where the tire starts). Had two different M/C shop guys tell me the problem couldn't be the slightly bent rim because the rotors float. I found a used rim and replaced the bent one (didn't know there are several places that will repair bent rims - do know now). Problem solved!
Oh - Have never gone back to the dealership.

Happy riding to all!

Ken

[sweatmark]

Thanks for the info! The bent wheel rim vs brake disk investigation advice could be valuable "down the road".

For future reference, who did you find for potential wheel repair?

[KB13]

My wife rides an "Asian" M/C and a local shop is really great with working on them. All the guys there are my age (50 -60) but they won't work on European bikes. They told me to call "1-800-mc-wheel" to get a bent aluminum wheel repaired. I tried Google searching on that but didn't find a website. Then did a search on "motorcycle, wheel, straighten" and found several sites. I can't recommend any but they advertise "perfection" for $130 - $160. Info for what it's worth.

[gregor]

I agree with the motor cycle shop guys diagnosis. Can not think why a 1/8" distortion of the rim edge only would cause brake pulsing with a floating disc.
Don't dismiss other experienced mechanics best advice as being nonsense- no one is perfect.

But an interesting outcome.

[new2merockster]

They do float but only to the outside. Those spring washers are on the outside pressing discs to the wheel- no free play there. You did the best thing by changing the rims. I don't think they would straighten it "perfectly". They would probably still require some milling where discs meet the rim.