Front Brakes Problem

[flyingmonkey]

CBR 600RR 04

I been having problems with my bike “front brakes”
The brake feels fine if the front tire does not move, when I move the front tire the brake does not have any pressure. I pump the brake again and then goes back to normal.
I change the calipers, I change the fluid but did not solve the problem, and then I move to the rotors (maybe they are bend), I got a used set of rotors “not sure if they are bend as well” and I continue to have the same problem.
Everything I research online is telling me the rotors are bend because when you move the front tire the rotors move the calipers side ways if they bend. This creates for the brake not to have any pressure.

Has anybody experience this problem?

[#1Townie]

Take it for a ride. While rolling slight pull the lever. If you feal it pulsing its the rotors.

[asp_125]

Yup, probably bent rotors. Had that on the old race bike. When the bent part hits the brake caliper it knocks the pads and cylinders back further into the caliper. So when the non-bent part comes around, the pads are too far to come all the way back to grip.

Do you own a dial indicator to measure runout? Of a simple spin of the wheel while looking down the edge of the rotor can sometimes tell.

[flyingmonkey]

when I got back home from my last track day i drop my bike on the right side and I am assuming the front side of the bike landed on the spare tire of the trailer, i am thinking it probably bend the rotor, could it also move the fork which connects to the brakets that hold the calipers and create this problem?
Before I persue and get new rotors I would like to make sure there are no other possibilities, the only place I find new low price rotors is in Ebay location hong kong, not sure if is safe to purchase stuff located in hong kong.

Thanks for all the help guys.

[maktastik_jr.]

I find new low price rotors is in Ebay location hong kong, not sure if is safe to purchase stuff located in hong kong.

Thanks for all the help guys.

i wouldnt. so many cheesy psuedo parts manufactures in hong kong. do your local motorcycle shop a favor and give them your business.

[asp_125]

when I got back home from my last track day i drop my bike on the right side and I am assuming the front side of the bike landed on the spare tire of the trailer, i am thinking it probably bend the rotor, could it also move the fork which connects to the brakets that hold the calipers and create this problem?
Before I persue and get new rotors I would like to make sure there are no other possibilities, the only place I find new low price rotors is in Ebay location hong kong, not sure if is safe to purchase stuff located in hong kong.

Thanks for all the help guys.

BTDT, that's how the track bike rotor got bent. Lost a strap while unloading and the bike tipped just enough in the Pingle chock to hit the rotor. Luckily found a rotor from another MRA racer for the weekend and was able to buy a straight one from Steeles. Threw away the Pingle chock after that, and invested in a real wheel chock that held the bike securely.

[flyingmonkey]

Sounds like you and I had the same experience, It is pretty clear I guess that the replacement used rotors I got are also bend and this is why I continue to have the same problem.
did your front brake work when the front tire did not move?
my front brake works if the front tire does not move, when I move it the front brake is completely out. i put pressure on the brake and it builds it back up again and works as long as the front tire does not move.
I am pretty sure my chock and the trailer spare tire hit the rotor when I lay down the bike on the trailer.

BTDT, that's how the track bike rotor got bent. Lost a strap while unloading and the bike tipped just enough in the Pingle chock to hit the rotor. Luckily found a rotor from another MRA racer for the weekend and was able to buy a straight one from Steeles. Threw away the Pingle chock after that, and invested in a real wheel chock that held the bike securely.

[asp_125]

Before concluding a bent rotor, there are a couple other checks you need to make.

1. that the forks did not get tweaked in the triple tree when the bike fell over. Measure them at various places relative to the frame; left and right sides should be nearly identical.

2. that the axle is not crooked. With the front wheel off the ground (on a stand), spin it and check for wobbles. At the same time look at the rotors from head on and check for wobbles.

3. check the brake caliper mounting, if the caliper got tweaked but the rotors are straight, you may get the same effect. Caliper and shoes should be parallel to the rotor.

If everything else is to spec and rotates true, the rotors are probably bent.

[flyingmonkey]

Thanks, I am planning to do some additional tests this weekend, if I can't find the solution I will take the front wheel to a proffesional test and see if they can tell me if the rotors I got and bend or not.
If I buy new rotors again I will have to get brand new ones for sure but I want to make sure that is the problem

Rotors are expensive but not braking can be even more expensive.

[gsxridiot]

i wouldnt buy another rotor from chini again.
spent 250.00 on a pair and they came warped new
waddya know,no response when i try to contact retailer
i would suggest a used one off the bay

[Repsol a095]

If they aren't that bad, woody's wheel can straighten them. It could be cheaper.

[flyingmonkey]

I will test a few things this sat morning. If it does not work i will head to woodys.

[flyingmonkey]

Did you buy a set from chini?
Was it a good set?




QUOTE=gsxridiot;702269]i wouldnt buy another rotor from chini again.
spent 250.00 on a pair and they came warped new
waddya know,no response when i try to contact retailer
i would suggest a used one off the bay[/QUOTE]

[flyingmonkey]

Rotors got fix and now the brakes work even better.
They were bend
Thanks for the help guys.