Front brake problem??

[fazza59]

Can someone advise me...

My R1 has developed a slight problem. Under slow speed braking (using front brake) the forks dip as thought the brake pads are binding. At high speeds this is not noticable.... I dont get any pulsing throught the lever! I know most will say the disks are warped but I dont think they are... Could it be sticking pistons? Or could it be something else???

Any suggestions would be great.
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Current - Yamaha R1 - Yamaha XJ600N - Kawasaki GPZ 500S (project? Maybe )
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[MarkJ]

Sounds like sticking pistons to me, you might be lucky and the discs haven't warped yet.

Go for a quick ride round the block, avoiding heavy braking, and see how hot the discs are when you get back.

[fazza59]

I have felt the disks after a long ride and they dont get hot! Thefront wheel spins freely so I dont suspect warped disks...
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Current - Yamaha R1 - Yamaha XJ600N - Kawasaki GPZ 500S (project? Maybe )
Pics of my bikes

[mad4it028]

[fazza59]

[MarkJ]

No oil in the forks? Have you blown a seal?

[fazza59]

Forks are fine... seals are fine...its the brakes or head bearings! Well thats my theory....
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Current - Yamaha R1 - Yamaha XJ600N - Kawasaki GPZ 500S (project? Maybe )
Pics of my bikes

[Digit]

I'm not familiar with your model but two things seem possible to me. Brake problem is one, but does the bike have anti dive? if so a a fault there could be a second possibility.

Roy.
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Happy daze!

[mad4it028]

out of shape front tyre?
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[MarkJ]

[fazza59]

No anti dive....tyre is fine....

Hard to explain.....but here goes....5mph ot less....slight front brake not much pressure...forks dive as you would expect as the front brake is applied...the the brakes feel as thought they release and the forks rise....then dip again as they bite..

but I have to say this is only at low speed.....at high speed all is fine??? thats what I cant understand
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Current - Yamaha R1 - Yamaha XJ600N - Kawasaki GPZ 500S (project? Maybe )
Pics of my bikes

[Ariel Badger]

Any uneven wear on the pads or air in the system?
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[loply]

Okay, so you have the text book perfect symptom of warped discs.

You say you don't think they are.

Any reason?

Because if you haven't taken them off and lay them on a sheet of glass then the logical answer is that you have warped discs.
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[MarkJ]

That certainly sounds to me like a warped disc or discs with seized pistons. I had it a few months ago - pistons were seized so you didn't get any pulsing on the lever as they wouldn't go back into the caliper to move the fluid against the master cylinder, but moved enough to brake. So when the wheel spun you got a braking force where the disc was warped out of shape and pushed against the pads then no force where it was normal.

You can do what loply says, or just take the calipers off the front wheel and spin the wheel. Look from the front as the wheel spins and you'll notice any warped discs because they won't stay true and will appear to weave.

[fazza59]

Ok so looks like it might be my worst fears ..... Was only hoping it was not a warped disk but looks like I might be wrong!!! Can anyone tell me if buying a set of wavy disks from china is a bad idea??! Looks like I'm gonna have to service the calipers as well. Had them off and one is sticking

Bugger
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Current - Yamaha R1 - Yamaha XJ600N - Kawasaki GPZ 500S (project? Maybe )
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[Digit]

There's only one problem with buying from China that I've experienced and that's boredom whilst awaiting delivery.

Roy.
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Happy daze!

[Noxious89123]