Brake juddering: THE SAGA CONTINUES.

**The Pastor** · 5th April 2007, 15:20

Originally Posted by pete376403

IMHO, juddering (ie shaking the whole bike)will be something bent or loose, whereas worn disks are more likely to give a pulsing through the brake lever.
When you've had the wheel out, have you grasped the fork sliders and see if you can feel any back and forth/side to side movement? Loosen the triple clamp bolts a bit and try rotating the fork leg -if its bent you'd see the bottom of the slider moving around (can't explain it but I'm sure you know what I mean)
Are the surfaces where the caliper bolts to the fork leg good / flat? Caliper bolt holes or sliding pin holes not worn? (if the fault happens at pushing speed it would seem the caliper(s) grab the disk and are moving a bit, either on the bolts or slider pins)
Remove 1 caliper - put something between the pads so they don't pop out then try it with only one side active? Any change? (try to narrow it down to one side).
Mudguard bolts tight? Guard mounts can act as a cheap fork brace
Do you know anyone with a similar bike that you could swap the wheel with?

whats a fork slider?

**pete376403** · 5th April 2007, 16:34

the ally bit at the bottom that bounces up and down - the moving part of the fork leg - jeeze don't they teach ANYTHING in school anymore?

**The Pastor** · 5th April 2007, 18:10

Nah its all picking up rubbish and patting your self on your back.

There doesnt seem to be any movement at all.

Disc's havnt arrived today, looks like it will come on saturday.

**Motu** · 5th April 2007, 18:58

Originally Posted by Speedie

He has actually given quite a good description of the problem Ixion, i.e. can feel brake lever pulsing when only pushing the bike along, this discounts most of your "options". I dont have any help for RM, but I would suggest your post is not awefully helpful, perhaps you could refine your answer a little to be more specific.

Back to basics - the problem with people diagnosing problems is they leap from one possibility to another,dismiss suggestions as ''no,I've checked that'' and ignore other ideas as ''No,it can't be that''.It's practically impossible to diagnose over the internet,and not helped by the person in question asking ''what's a fork slider?'' Personally I'm not even going to bother.

**The Pastor** · 5th April 2007, 19:10

Hey, im learning alright, I guessed that was a fork slider, but wasnt sure so I asked. Its fine with me if you don't want to share you knowledge.

**crazybigal** · 5th April 2007, 19:37

its called a "stanchion" did they not teach you that at school?

Originally Posted by pete376403

the ally bit at the bottom that bounces up and down - the moving part of the fork leg - jeeze don't they teach ANYTHING in school anymore?

**crazybigal** · 5th April 2007, 19:51

what state is your front tyre in? is it wearing un evenly?
ive had bad wheel alignments wear out tyres and under braking you can feel
it. just my 2 cents, you have changed the fluid havnt you?
make sure your alignment is good, dont go by the marks on your swing arm.
i run 2 steel bars down the bike clamped to the rear wheel and measure the distance between the bars, both front and back then the distance from the front wheel to the bar on either side.
id say its more a wheel problem since your discs are good and your brake pads and caliper are good (no stuck pistons) also make sure your pads dont have a glaze on them.
hope you figure it out!

**Ixion** · 5th April 2007, 20:02

Originally Posted by crazybigal

its called a "stanchion" did they not teach you that at school?

No, the staunchion is the fixed bit that is clamped in the yokes (USD forks are a bit anomalous). The movy up and downy bit, that the wheel is fixed to, is the slider. Cos it slides. The fixed tube is the staunchion. Cos it's staunch.

**The Pastor** · 5th April 2007, 21:02

Originally Posted by crazybigal

what state is your front tyre in? is it wearing un evenly?
ive had bad wheel alignments wear out tyres and under braking you can feel
it. just my 2 cents, you have changed the fluid havnt you?
make sure your alignment is good, dont go by the marks on your swing arm.
i run 2 steel bars down the bike clamped to the rear wheel and measure the distance between the bars, both front and back then the distance from the front wheel to the bar on either side.
id say its more a wheel problem since your discs are good and your brake pads and caliper are good (no stuck pistons) also make sure your pads dont have a glaze on them.
hope you figure it out!

Yeah When I get my discs back i'll try it out, my best guess at this stage is its wheel alignment or a bent axle, I didnt know wheel out of alignment could even do that!

**doc** · 5th April 2007, 21:10

Originally Posted by Motu

Back to basics - the problem with people diagnosing problems is they leap from one possibility to another,dismiss suggestions as ''no,I've checked that'' and ignore other ideas as ''No,it can't be that''.It's practically impossible to diagnose over the internet,and not helped by the person in question asking ''what's a fork slider?'' Personally I'm not even going to bother.

Motu you disappoint me. What about checkin the fuel level first. Back to basics. Never a truer word was said in jest stuff.

**Drum** · 5th April 2007, 21:29

Sorry, couldn't be bothered reading it all.........did anyone suggest that the fork oil level could be too high?

**Brett** · 5th April 2007, 21:55

I do believe you may have the issue that I do at present. Under hard braking every now and again I get a shuddering effect that is NOT the same as bent rotor pulsing. I think that I have got air bubbles in my hydraulic fluid, and will be replacing it tomorrow if I can be arsed. Will let you know how I get on and whether it works.

Can anyone confirm that DOT 5.1 Elf racing brake fluid is sweet in a gixxer?? I bought the stuff for my 200sx when i upgraded the brakes on that, but have since sold the car and now have enough to do the gsxr instead...

**riffer** · 5th April 2007, 22:09

Hmmm. Brett - how long has your brake fluid been sitting? Is it unopened? If it isn't you might as well throw it away. Brake fluid is hygroscopic, which means it absorbs moisture from the air, degrading its performance.

**Brett** · 5th April 2007, 22:19

Originally Posted by riffer

Hmmm. Brett - how long has your brake fluid been sitting? Is it unopened? If it isn't you might as well throw it away. Brake fluid is hygroscopic, which means it absorbs moisture from the air, degrading its performance.

Was only a few months old, in an un-opened bottle so would still be perfect, however I just checked it, and it is silicon based and as such not suitable for my brake system. Will have to find some good dot 4 stuff...only no shops open tomorrow, may have to wait till Saturday.