750 Sport front brakes

[750sport]

Our 750 Sport has been fitted with the dual front brake set up. Please see my post here

In my mind if the rotors are slightly warped that isn't a big problem as the pads within the calipers should float with the warp, however, if the thickness of the rotors changes as it rotates then that will cause uneven braking and a pulsing brake leaver (which this bike has). The uneven braking is very apparent at low speed. Measurements with a micrometer show the thikness differs by up to 0.1mm.

Upon considering the effect of the uneven thickness I guess this could also result in the non effected disk to "grab" as the pressure in the brake system would increase on that side as well (as well as being felt in the leaver). The result, increase in braking on the uneven disc due to mechanics, increase in braking on the non effected disc due to hydraulics.

The disc that is in question is also thinnner than the other one which suggests it has been machined once before - perhaps its wasn't a great job - not sure.

Today we are making a jig to enable the machining of both rotors on a lathe while still mounted on the hub that comes away with the rotor, this I hope will sort it out.

Are there any pointers that you can give when setting the front brakes up? Any traps?

Thanks all.

[BevHevSteve]

if you can cut BOTH sides of a disk at the same time, like they do for car disk brakes you are in business. Be carefull to not cut too much and make the disk too thin..........

Once you do this see how she goes.

You have F08 calipers so pistons, seals etc are all readily available here and elsewhere. Remember brembo seals are natural rubber so MOTUL RACING 600 or BREMBO LCF600 only - don;t use any new type fluids

[750sport]

Thanks Steve. Our intention was to machine both sides before unmounting form the jig on the lathe, that way both sides will be parrallel to each other for sure.

Thanks for the tip on the brakes, I'll go grab some of the appropriate brake fluid.

[Den]

These are interesting:

http://www.stoptech.com/tech_info/wp_wa ... disk.shtml

http://www.stoptech.com/tech_info/wp_be ... ents.shtml

[cafe*racer]

Thought I would revive this thread as there seems to be some mileage to be had. Correct me if I am wrong Steve, but I think when you said

if you can cut BOTH sides of a disk at the same time

that you meant both cuts had to be made on both sides of the disk simultaneously. Obviously this would be to prevent deflection of the disk while cutting, a common problem in machining even seemingly heavy items. I have yet to find a local outfit that has the equipment to do this. Most look at the rotor and shake their collective head. There must be a solution for the back yard machinist (that's kinda somewhere between shade tree and professional) like myself.