Warped discs? Maybe not...

[martybabe]

For those with the mechanical diagnosis gene missing, like me.

I had convinced myself I had a warped disc or two on my GSX1400, all the symptoms were there, pulsating lever, juddering braking action etc. Unlike my previous encounters with this malady on other bikes,the pulsating was accompanied by a clattery rattle noise, most annoying when slowing down for a junction, clack clack clack.

Anyway, I'd been putting off buying some new ones due to the difficulty in obtaining them and the price and not knowing if you're buying Chinese tin off the interweb, when quite randomly and for no justifiable reason I can think of, I gave the front wheel a hefty boot whilst walking round the garage feeling sorry for myself. To my surprise the clattery noise was evident and on further investigation and more booting,I discovered when I put pressure on the anti- screech plate on the right hand calliper, the noise stopped ?

One of the brake pads was actually free moving on the pin, unlike the other three which were held softly but firmly against the discs.Suspecting some of the 6 pistons were not moving in and or out freely, I removed the calliper, extended the pistons as far as I dared, cleaned them all up with brake cleaner and lubricated all the relevant parts with high temperature grease.

Road testing a while later, I was expecting the clatter to be improved but to my surprise, there was no clatter at all, in fact none of the previous symptoms were evident, no pulsing, no clatter, no judder. Result!

I've saved myself anywhere between $500 and $800 just by servicing the callipers. Now I'm not saying your discs or not warped all I'm saying, by way of a heads up, is that giving your Callipers a thorough sorting maybe a worthwhile venture before you lay out lots of money on very expensive replacement discs.

I hope this is of use to somebody somewhere sometime, all the best MB

[dino3310]

well done matey, caliper servicing is overlooked by a lot of riders i know i'm guilty

[vifferman]

Good stuff!
I had a similar situation when I bought my VFR. The right front disc pulsed badly, even after I removed areas of corrosion from the disc's surface. I figured it was borkt, and asked the "bike shop who will be nameless because they're dicks" to check it for runout. They said it was "within tolerance". Whether they checked it or not, I really don't know.
So, I just put up with it for 6 months, until it failed the first WOF, because the brake pads were 'ted. The replacement ones fixed the problem.

[riffer]

Yes, calipers quite often can give you this problem.

Don't forget also to grease the sliders the pads can run in - quite often they can stick on these - you even sometimes need to get some wet and dry paper and clean up these slide bars to get a real smooth surface.

Forks not liking the fork oil can give a shudder too. Changing the fork oil, or even using a different brand of oil can make a real difference. It did for me.

[Mikkel]

If you suspect that you have a warped disc, it isn't too difficult to measure it.

You just need a front stand to get the wheel off the ground and a vernier caliper. If the disc isn't out, it'll have to be something else