Motorcycle Repair: honda vfr750 front brake problem, caliper pistons, honda vfr750

Question
Hi,thanks for looking at this. at the weekend while i was putting my bike on the centrestand, i lost my balance & the bike went over on its right side. the drop was gentle, as i managed to hold onto it as it went down, so it was not a bang, just a matter of gently letting it go down. now i have a problem with the front brakes. they have siezed in the on position & i cannot get them to work properly. the problem is that when i tried to push the pistons back into the caliper, i could only push them back in a little way. when i reapplied the brake lever, they siezed again. i have not noticed any components that are bent or warped & cannot work out what is wrong. the only other thing i can add is that the brake lever is slightly bent outwards, otherwise, i am stuck for a solution. can you help at all? any assistance would be gratefully received. thanks, Alan.

Answer
Hi Alan...

Wow.. tuff question. Being as how the brake lever was bent outward, I am at a loss to understand how this mishap has caused the problem. It may be a coincidence. But at anyrate, we need to determine where the problem is exactly. A VFR750 Interceptor has a dual front disc brake system. That means you have calipers on both sides of the front wheel. I would suspect that the weight of the bike landing on the right side (the side that has the brake lever) has actuated the brakes harder then they would usually be activated. This may have forced one of the set of caliper pistons outward and they aren't retracting due to dirt and yuk build up. Or, one of the piston seals has dislodged from it's seat and is now jamming the piston in the outward position. Here's what ya do... put the bike on the centerstand... (carefully Alan.. LOL), then put a jack under the front of the engine in a safe place (don't damage anything) so as to raise the front wheel off the ground. Ya only need to get it up enough to allow the front wheel to rotate. Now take a plastic tipped hammer and smack the outside of the caliper piston housings on both calipers... this should free the wheel so it can spin. Now remove one of the calipers and insert a piece of wood (roughly the same thickness as the rotor) between the brake pads. Once inserted, spin the wheel briskly and actuate the front brake. The wheel should of course stop. Release the brake lever and see if the wheel spins freely. If it does, then the problem is in the other caliper (the one you removed and stuck the strip of wood in) If it doesn't spin freely, then the problem is in the caliper that you didn't remove. You will then need a brake piston seal kit and will need to remove the pistons from the offending caliper and install new seals. While doing so, make sure to inspect the pistons while they are out... they need to be clean and free of rust and pitting. You may need to get the proper repair manual for your bike to help you along on rebuilding the caliper, but it really isn't too hard. This should get you on the right track. If ya need more help.. just ask!! That's what we are here for! Good luck Alan..

Jack