bent rotors

[tri boy]

Or they are knocked, or of poor quality, or there is misalignment with hub bore/axle angle or one or two other reasons. But yes, excessive localised heat from stationary disc/pad after a hard braking session is probably the most common cause.
Either way, it an expensive change out component in NZ. We pay FAR TOO MUCH for M/Cycle rotors.

[MSTRS:Me]

Either way, it an expensive change out component in NZ. We pay FAR TOO MUCH for M/Cycle rotors.

The big +1 to that....criminal it is.

[FROSTY:Me]

Hey boomer I know this sounds silly but have you -or has anyone actually done a static balance on the NAKED wheel/wheels?
Im wondering if the tyres are the symptom not the cause.
Ie --the WHEEL or wheels have a heavy spot

[riffer]

Wouldn't that manifest itself as an out-of-balance shudder at varying velocities though, and sometimes no shuddering?

[FROSTY:Me]

would do/might do--but remember there are balance weights being used
to bring it "back into trim"

[riffer]

Good point.

I'd still be getting those rotors checked with a dial-out gauge before going further. If there is clear irrefutable evidence that there's some out-of-trueness here and its obviously not been caused by some external force like being banged then there may be a case for a warranty claim.

The damn trouble is if you thrash the bike you quite often warp the rotors.

How hard are you on the bike boomer?

[boomer]

the shop, after taking the wheel of to measure the tolerances, told me the front tyre/wheel was out of balance. So they rebalanced it for me. ( remembering this wheel was fitted one week prior at another shop )

Cycletreads did tell me that the rear (wheel only) was out by 4gms when i had the fun and games with the last set of tyres?!

i'm at a loss what to do. In fact it's gone into the cant be bothered bucket at the moment.


i'd like to find a shop, preferably a Suzuki dealer, who i can go to where they are meticulous in there work and standards and i know i can trust... rather than getting the run around.

here's something worth noting; the bike hasn't been knocked however it has been on 2 track days. If there is a method for using brakes..i.e warming them up/down then why isn't this included in the user manual?

[imdying]

i'm at a loss what to do. In fact it's gone into the cant be bothered bucket at the moment.

Which I'm picking is exactly what they want.

Rotors are like cranks, if they get abused they die and cost a reasonable lump of coin to fix. If you've not abused the bike, and it's under warranty, then that's not your problem though.

You need to visit a brake specialist, that 0800 race brakes guy will do. I'd do it myself, but yeah... 1000kms to measure you disc thickness variation and runout relative to the calipers etc, bit overkill. That guy has a good rep, get him to measure it and write the facts down... even if you have to pay him, you can always jump up and down and have Suzuki pay that back later.

You make an interesting point re the user manual, it is possible to damage them by cooling them down to quick, or leaving hot pads on them, so maybe they should mention it, like they do about say redlining the motor.

I've no idea it track days and stuff are covered under warranty, if you've done any.

[Toast]

Hey boomer I know this sounds silly but have you -or has anyone actually done a static balance on the NAKED wheel/wheels?
Im wondering if the tyres are the symptom not the cause.
Ie --the WHEEL or wheels have a heavy spot

It shouldn't matter if the wheel is out of balance. Infact most (especially Suzuki cheese metal rims) are. I've stuck a mate's Gixxer thou' rim on the balance machine and it was about 90 grams out.

It was even worse when the tyre went on, but once the whole package was balanced with weights, there was no issue riding the bike.

The only thing that is harmed by having a bunch of weights on the edge of the rim is that the moment of inertia of the wheel/tyre package is increased, reducing performance.

Could be more to it, but the wheel being out of balance doesn't seem like the issue. I'm bemused by the fact that every tyre that goes on one of his rims ends up out of balance a week later.

[boomer]

It shouldn't matter if the wheel is out of balance. Infact most (especially Suzuki cheese metal rims) are. I've stuck a mate's Gixxer thou' rim on the balance machine and it was about 90 grams out.

It was even worse when the tyre went on, but once the whole package was balanced with weights, there was no issue riding the bike.

The only thing that is harmed by having a bunch of weights on the edge of the rim is that the moment of inertia of the wheel/tyre package is increased, reducing performance.

Could be more to it, but the wheel being out of balance doesn't seem like the issue. I'm bemused by the fact that every tyre that goes on one of his rims ends up out of balance a week later.

you and me both mate... I caught up with Phil at BBT and mentioned the out of balance front rim. He looked confused and quickly changed the subject.


ahahaha

[Pancakes]

This is only one story of soooo many about the motorbike industry in general. And for what they charge you think you could just get a straight answer a quote and it fixed. Problems happen, how come people who recon they're shit hot mechanics (and charge accordingly) do a job like a wheel balance wrong? and have it "go out' again too. If it's rider caused they should be able to point to a big flat spot where he's been doing broadside skids steelriders style. I think everyone wants to know how a wheel is going to change weights so dramatically thru normal riding.

[codgyoleracer]

Did you get this sorted Boomer ?, are the discs warped as in "dished outward" or are they bent as in "there edges can be seen to move in & out as the wheel is spun"
Glen

[Oldfulla]

well I have had the same problem. Went to the last KB track day a couple of weeks back. Went too hard on the braking and warped the brake discs. just had the quote back from the shop, $420 per disc with pads, and that isnt even geniune parts. So its going to be around $1000 all up to get it fixed.

So moral of the story, treat ya bike with care, get soft compond brake pads so they dont over heat or its gunna cost lots.

[terbang]

Brake discs (rotors) warped, still warp and are likely to continue to warp for years to come. They get hot and they are made of steel... My neighbour (ZX14) and I have both had tyres balanced at Cycltreads in Takapuna and both had balance troubles. Reckon their machine is dodgey or something. Maybe just a coincidence as well.

[Maido]

I have had "shuddering" brakes on my last 2 race bikes (might be a Honda thing?). It would only happen on certain corners on certain tracks (eg the first left after the infield sweeper at ruapuna and turn one at teretonga) When applying brakes here it feels just like ABS through the lever.
As pointed out in up above, with a warp in the disk each time it spins it is trying to push the brake pads out back into the calliper, The constant movement of the pads and pistons in and out results in the lever getting a pulsing feeling.
To combat this we removed the inner most rivet shim on the disks. therefore making the disks "fully floating". The result meant that when brakes are applied the disks have more "float" so they can centralise themselves much better in the callipers, meaning that any little warps have no effect on braking.

It is an easy but time consuming task that you can do your self with a set of $2 screw drivers from dick smith!