this'll prob get moved to tech but im tryin to get the most help on it or ideas fast.


ok. so last year i bought a wrecked 05 gsxr 750, since ive replaced things as needed frame and the whole front end. im having this brake problem where

-the front brakes work while the bikes stationary but after a few pumps. when i go down the street though they are worthless to slow me down.

i have replaced the following

-master cylinder *ebay
-front rim *spare
i used the existing rotors and calipers and this was completely useless


in the past weeks especially today i've replaced
-another master + lines + calipers *ebay suncoast cycles
-rotors *individual ebayer
-front rim *my 02 750 track bike so its proven straight
-front axle *my 02 750 track bike

i just took the front rim off my 02 750 this morning after goin on a short ride to make sure again it was completely functional and it is.

so currently the bike has a completely replaced front end

ive tried bleeding the front brakes with a hand pump bleeder at all points. friday i closed all bleeders, took the res. cap off, pulled the lever in half way n tied it off until this morning and still have the problem.

PLEASE HELP.... the rotors look good but are the only things i can think of

 

try brake pads...are they worn??? do you have good feel on the lever??? sounds like you have fork oil or something on u're pads

 

I don't get why that would be the rotors.

No fluid is leaking anywhere??

 

either bad caliper or mastercylinder
if rotors were junk they wouldnt be locking up

 

do you have good pressure or is that your problem? if you have pressure(good pressure) and it still feels like it takes time to bite you probably have worn pads or got fluid on them. mastercylinders and calipers hardly blow seals.if it was the rotors they would either be warped and you'd feel it the first time down the street or they are grooved bad.get those pads hot! to try to burn them into the rotors and get the fluid off them.

 

It sounds like the master cylinder could be bad, but since you've replaced it twice, that's probably not likely. When you pump it up until you get pressure, does it hold that pressure for as long as you hold the lever? If not, then you have a leak or a bad master cylinder. Bad calipers would leak brake fluid out, but a bad master cylinder would just leak the fluid back into the reservoir.

 

bleed them again and ride the bike... keep using the brakes and see if they start working better. then you may want to bleed them once more.

 

hey u got a new avatar

 

thanks everyone so far. i got no leaks anywhere, forks are aligned right and everything. when the bike is stationary the brakes are great, the correct feel and everything. but going down the street its worthless the lever just pulls to the bar.

ive bleed and bleed all last week. however, the local guru said that u get that problem when the rotors are warped. the rotors from the original busted rim looked fine but how bad the rim was i replaced them anyways.

today i swapped the front rim and axle off my 02 which i know is solid and rode that a while before the swap.

the only thing i think it could be is the rotors, i ebayed em for like $50 shipped. im goin out now to try n measure straightness with the screwdriver trick and im callin the guru tomarrow to see about getting them re bleed.

 

the question is ........is it him thought or just another of stock 05

 

the local guru is a dumb ***.... if the rotors were warped you'd feel the lever pulsing.

you probably just need to give them time, if you got fluid on the pads its gonna take a few miles to get them stopping good again. my 929 caliper on my hand brake was like that... no air in it, it just took a day or 2 of normal riding to get it worked in. just try it......

 

another? where was the first?

yeah thats a pic of HOMO05, dude thinks hes on some ****.... woo hoo.... a one hander.... big ******* deal!

 

not exactly if the rotor is warped how would you can not feel it in the lever if the piston or pistons were pushed back on the first rotation..... happened to me in the middle of a race clipped someones back tire and tweaked the rotor lost front brakes costed me 2nd place in a gncc.

 

yeah dude i feel your pain.... im in the exact same situation where everything feels right when stopped but once you get out going it goes to ****....

checked all the same stuff.... lines, master, pads, rotors.....

**** wont stoppie anymore to save its life....

 

Def Rotors. They Are Tight When Your Stopped Because The Bend Has Not Pushed Your Brake Pads Out Yet.when You Start Moving The Bend Will Spread Your Pads Giving You That Turd Feel. You Can Usually Pump The Brake Really Fast Until It Gets A Little Pressure And Hold It So You Can Feel The Warp.

 

youre an idiot. the local guy owns his own shop full of bikes that he successfully fixes, has owners pick up and new ones in every week from all over norcal. takes weekends off because he races on them. he even said the rotors were probably bent as i had thought. i just put the front end up, took calipers off, a flood light and a tape measure..... THEM ROTORS ARE BENT! 1/4" WARPAGEDEDED!!!!!!!!!!!

oh yeah, stock 05 used to have a pic on his myspace on his sf red f4i, i think in jean shorts and a field armor and black shoes.



you hit anything? i heard you can have too much pressure in your breaks also. i thought it may have even been the axle but eyeing the sidewall n spinning the wheel its consistent no wobbles so that means the rim axle and pretty much the bearings too are gangster status.


its kinda weird that if u have a warped rotor n u murder the brake lever it doesnt work and go closer/further from the clip on as u hit the warped spot. instead.... its about as worthless as trying to hang someone with wet top ramen

 

glad you found it i never thought about the light trick i just took off the rotor and laid it down on a flat surface.

not trying to be rude........but now that you found it dont it seem so easy and logical......i thought so myself took me 3 days to find it couldnt figure it out and i was getting madder than hell too.

 

lol, yeah, sorry the lights just cus its dark out here, the tape measure will give u an idea of how bad the warpage is. i tried the flat surface but the rivets on the rotor wont let it lay completely flat and also can be moderately decieveing with the table trick. *i got a round glass table in the back*

 

yea it dont take much to do it