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CBR1000 2006 help needed with judder

2K views 11 replies 7 participants last post by  oldbastard 
#1 ·
Hi guys. Im from singapore and need some help..

For the past 8 weeks I've been having a nightmare of a time with my blade.

Initially when braking from 50 to zero ; the brake lever would pulsate and the bike would jerk back and forth. Also when braking from 80/90 - 0 ... there would be alot of vibrations till about 70kmh where it would just stop vibrating.

So i changed new oem rotors

The problem stopped for 3 weeks but started slowly coming back and now its back again..

So changed the steering head bearing , calipers serviced with new o rings and fresh grease , new SBS sinter pads .. wheel bearings are 2 months old as well.

But even after this i still get a minor brake lever pulse at low speed and crazy shuddering/left right vibrations when hard braking at 80/90 kmh but goes away once im at 70..

It only has minor shuddering above 120kmh and at times disappears when im above 180 kmh and braking..

The worst is at 80/90kmh

Anyone experienced this before ? Or any inputs ?

Appreciate the help .. need to solve this asap

Thanks
 
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#3 ·
Sounds like it could possibly be coming front the front wheel. Check that the front wheel is true, the new bearings are fitted properly (and haven't failed) that there's no damage on the wheel rim and that it's properly fitted to the forks. You really need to get the font end up in the air loose without it resting on a paddock stand to check everything properly.
 
#8 ·
Why on earth wouldn't you change the pads, especially if the rotor change is chasing a problem?

Your assertion that changing them all together is 'an old wives tale' is not only ridiculous, it's potentially misleading to people that come to sites like this for advice, unless you have specific data to contradict every brake expert and vehicle manufacturer on the planet?
 
#9 ·
Why on earth wouldn't you change the pads, especially if the rotor change is chasing a problem?

Your assertion that changing them all together is 'an old wives tale' is not only ridiculous, it's potentially misleading to people that come to sites like this for advice, unless you have specific data to contradict every brake expert and vehicle manufacturer on the planet?
Brake pads are routinely replaced as a wear item while rotors have usable service life remaining. They are not a matched set, otherwise they would have the same wear rates. It is tradition and considered good practice to change pads when rotors are replaced because of old process and machining techniques when rotors are made. Some manufacturers are revising these practices much in the same way that the old advice of changing oil 3mos or 3,000 miles is being revised.

Saying OWT would be better stated that its an out-moded de facto practice.

I'm not against changing the pads; it might be warranted in this case, but I wouldn't do it as a knee jerk reaction to changing rotors.
 
#10 ·
There is cars and there is motorcycles. Sure you could have had new pads installed 1,000 miles and then warped a rotor and the pads wouldn't be changed, just the rotor. By normally people are going in not for a warped rotor but because the pads need to be replaced, then the rotors are inspected and measured. This is when they are found that they need to be replaced. Normally people are not going in because their rotors are under the minimum thickness as they are not even looking at those.

On a motorcycle, how many people get a warped rotor? Normally it is that the pads need to be replaced and the rotor is found to be below the minimum thickness. In this case, if someone has a braking problem and they are replacing the rotors, it would make sense to replace the pads. The rotors cost more than the pads do, so why not do the complete job?

Many manufacturers have moved away form the 3 months 3,000 miles. Many vehicles tell you the oil life so you know when to go in. Some still do time based as well, like 1 year or 10,000 miles whichever comes first. I would guess very few vehicles are going with the 3 months 3,000 miles schedule anymore per the manual.
 
#11 · (Edited)
There is cars and there is motorcycles. Sure you could have had new pads installed 1,000 miles and then warped a rotor and the pads wouldn't be changed, just the rotor. By normally people are going in not for a warped rotor but because the pads need to be replaced, then the rotors are inspected and measured. This is when they are found that they need to be replaced. Normally people are not going in because their rotors are under the minimum thickness as they are not even looking at those.

On a motorcycle, how many people get a warped rotor? Normally it is that the pads need to be replaced and the rotor is found to be below the minimum thickness. In this case, if someone has a braking problem and they are replacing the rotors, it would make sense to replace the pads. The rotors cost more than the pads do, so why not do the complete job?

Many manufacturers have moved away form the 3 months 3,000 miles. Many vehicles tell you the oil life so you know when to go in. Some still do time based as well, like 1 year or 10,000 miles whichever comes first. I would guess very few vehicles are going with the 3 months 3,000 miles schedule anymore per the manual.
The OP is trying to diagnose a problem. I don't believe in throwing parts at a problem hoping that something will solve it. This is why I don't agree with de facto advice to change the pads- we don' t know the cause of his problem and therefore don't know the solution. He indicated a 3 week cessation of the symptoms after changing the rotors and that's all we know- not enough IMO to make a definitive assessment which is why I agreed with Gunk that the wheel needs to be spun to get more information on what's happening. Once that's done we can make further assessments of other componentry if the results are negative.
 
#12 · (Edited)
Perhaps a key fact here is that the vibration seems worst at a particular speed. That speaks to me of an out-of-balance wheel causing resonance in the suspension/steering. Kriscratch (OP) talks about left-right shaking, that suggests that the wheel is not correctly dynamically balanced. Static balancing is usually ok for front wheels because they are relatively narrow, but if there is a big discrepancy between the centre of mass of the wheel left/right, then it will try to wobble, causing the bars to wobble left/right as he describes.
What I find strange though is that it apparently only happens during braking. Does it shake at any other speed without braking? when the brakes grab the disc it changes the whole dynamics of the assembly of course....
Even more strange is that the change of rotors fixed the problem but only for a while.....I'm struggling to think of what could have changed about the new discs or wheel assembly over a 3 week period. Can't be bearings, they were changed. Is the tyre ok? No strange gradual deformation taking place? Are the rotor carrier bolts tight? I'd strongly recommend getting the front wheel re-balanced. On a dynamic balancing rig (and get them to spin it up to 80km/h if possible), not static. If that checks out ok then you'll have to look at the forks.

(edit) after thinking about it, it still doesn't make sense. the biggest question is, why did changing the ROTORS fix the problem but only for a while? That would suggest there was something wrong with the originals (warped for instance) and the new ones corrected the problem but then somehow the problem came back. I can't believe the new rotors have become bent....that needs checking of course....
Agree with Jaybird. More info needed.
 
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