[xp rc51]

ok, so itook my rc for her first run the other day and the brakes felt a bit spongy. i figured air or bad fluid so i did a complete flush. no air nothing. bled out perfectly. prblem is the brake feel didnt improve much. now im coming off an 06 1000rr and the brakes on that are super touchy and sensitive. am i just being overly critical on the bike. is it not a fair comparison or do i possibly have a bad caliper? tell me how your brakes feel. and if you know of a possible remedy.
(i am running stainless steel galfer lines to the front, pads are great and i even tried working the caliper in and out several times to see if they were sticking. no luck with any of this)

 

[darisb]

I'll start by saying that I am not an expert. The brakes on my '03 grab harder than any my other three bikse. From experience spongy brakes are usually caused by contaminated fluid or rubber brake lines that are swelling when the brakes are applied. If you replaced the fluid and you do not see any leaks at the calipers, then I would guess it's the brake lines. The other possibility would be a leaky seal in the master cylinder, which is letting the brake fluid back into the reseviour instead of compressing it toward the calipers.

 

[xp rc51]

well i have no external leaks and the stainless braided lines, so its not that, but how do i check the master cylinder?

 

[darisb]

You'll have to check the manual for the exact procedure to test the master cylinder. One thing you might try..... I replaced the bars on a non-RC51. I wanted to reposition the brake line. One expert on that bike, advised that the front brakes on that bike were a bitch to bleed. Another user replied that you could tie back the brake lever (in the actuated position) over night, and any air in the line would travel upward toward the reservoir. I haven't tried it myself, but it's easy enough to try.

 

[misiek]

i noticed the same problem on mine.... took it out of stoarge after a few weeks and the brakes felt spongy... i might try the tie down trick before i get it tuned up for the season by my mechanic

 

[xp rc51]

ill give it a try