What would cause the bite point of the front brakes to wander? Ive got an RR7 that im using as a track bike. It has braided brake lines but other than that stock. The front brake bite point would change and often really close to the bar until maxing it out on hard braking and terrible. I bled the brakes but subtle change, decided the master cylinder was knackered and invested in a fancy brembo one (brand new). After fitting and lots of bleeding brake feel is much better but still the bite point wanders. Initially it starts far out with little movement of lever before hard bite..brilliant but very quickly moves a lot closer to the bar before hard bite. When riding hard on track its very unsettling not knowing what im going to get. What would be the cause?
I tore down and fully serviced both callipers, was some pitting on pistons so bought a second set of low milage callipers in much better condition. New seals and fully serviced. Issue persists. Will have a go at freeing the bobbins and see how good/bad they are
If it pulses as you're braking then it's more than likely something to do with the discs/bobbins/etc. It doesn't sound like that's the case though. They're really simple systems so either your brake lever is badly adjusted, the fluid is knackered, the master cylinder is knackered, the hose is knackered or the calipers are. Does it always feel consistent at a standstill before you ride it? Check the play on the brake lever to make sure that you're not constantly applying even a small amount of pressure to the brakes as you ride. If you do this the heat will build really quickly and your fluid or pads could go outside their operating range and start acting oddly. The second thing I'd do is flush the fluid and replace with new just to eliminate that. I'd do this anyway, especially once you've found the issue. The next thing I'd do is pull the pads and see what the wear is like. If it's consistent across all the pads then you can move on but what I'd be looking for would be more wear or discolouration on either end or top or bottom of any of the pads. This would indicate that the force on the pad is uneven resulting from a jammed piston or slider. This could give you the feeling you had because the temperature across any pad that isn't pushed squarely on to the disc will be all over the place and could heat the caliper in one spot and therefore the fluid which could make it feel really odd. If all the pads look ok and the pistons are free and moving evenly when you apply pressure and you're confident the hoses are good and the lever is adjusted it really only comes down to the master cylinder. Unless you've got abs of course and then all bets are off and I've no idea.
