Hello all. I've recently attempted to fit up some GSXR1000 calipers. I bought them off e-bay and disassembled them when I received them. Cleaned all the seals, grooves and all the brake fluid passageways. After a good bleeding, I had a really spongy lever. Taking them off, I noticed only one side of the pistons is extended. Any thoughts to this? I'm about to take them apart again and inspect, but I wanted to know if anyone else has had any issues like this. I'm coming up on a nice road trip with my dad to southwest CO, so if I can't sort this out, I'm more than likely going to go back to the stock setup. Any help is appreciated, thanks!!

 

if you mean only one piston extends, and the other stays put, that is common. The other should move though if you resist the movement of the other piston. Put some pressure on the one that is moving to resist it and check. If the second moves its probably OK. You can also put a spacer of some kind in there (wood is soft enough to not mar anything) and pump the lever. should get very firm or you either still have some air, or a bad Master cylinder. Likely air.

 

i was worried it'd be the master cylinder. i guess I'll try to source a working 5/8" master just in case. pisses me off a bit that they're not working 100%. good advice though, i'll check that out.

 

Went through the gsxr master, everything looked great. Leads me to believe it's soethingetting air in, so I Teflon taped the bleeder screws, ordered a master cylinder banjo bleeder bolt and will pick up some new crush washers tomorrow. Hopefully that fixes everything!!

 

Just installed the banjo bleeder screw and some new crush washers at all unions. That certainly helped a LOT!! Lever feels as it should now, so I'm all good! Hopefully finish the shakedown rides this weekend.