Knock from the front brake(s - 1980 GS1000G

[Guest]

I've a slight knock per revolution of the disc one one of my calipers.
I thought it was because a part was missing, now I'm not so sure..
The single caliper 'piston side pad shim' is in place on both calipers and the single pad spring is in place per caliper.

There are also 2 small top and bottom shims in place on the removable section of the caliper. I'm sure it's only one caliper that is offending.

It's really bugging me, any ideas?

Thank you.

[steve murdoch]

Could it be a warped rotor?

[AMK]

My caliper knocked but only when I first applied the brake and only once. I found the bolts to be loose.
Yours sounds like you should check for a cracked disc or a heat rise.

[mmattockx]

Could it be a warped rotor?

That would be my first guess as well.


Mark

[hillsy]

Take off your speedo cable and try it.

You never know - sometimes noises don't come from where you think they should....

[tools99]

knock goes away as soon as I touch the brake too, even very very slight grab on the lever.

[tools99]

I'll definitely try removing the cable to rule out the speedo drive, good idea

[salty_monk]

If it goes away when you pull the lever it's likely to be:

1. Warped rotor
2. Loose bolts
3. Warn sliding pins on the caliper (so the body wobbles about on the pins).

Check that there are no other obstructions (such as the speedo cable bracket being twisted and touching something, the speedo drive dust cover being dented & catching on the speedo drive etc).

[smilinbrad]

One time, when I had new tires installed at the shop, I ended up with a knock in my front wheel when I used the brakes.
I took the bike back and when they pulled the wheel off again they noticed they had not aligned the ears/notches on the speedo drive/pick up correctly.
I've made the same mistake myself when pulling the wheels.
Easy fix for me.