bent rotors

[boomer]

ok.. so i've had shit brakes since i bought the bike, a k7 1000.

so i replaced the lines with hel braided lines which made 'em a bit better but i seem to have warped rotors now.

So i've asked the shop and they measiured 'em and said yeah they're spotted and warped; he didnt tell me by how much.

So they asked Suzuki NZ to come to the party and a week later Suzuki says..... the rotors don't warp!

umm.. ok i say to the shop.. so i'm a bit bemused.. your saying theyre warped and suzuki says thats not possible.. unless they've been banged. The bikes mint and never been nocked.


So anyways Suzuki NZ tell the shop that they can fix them easily enough.. by taking the bike out and heating up the brakes & rotors .. i.e ride the bike hard with the front brakes applied... as... and here's the punch line... the rotors/steel remember there original shape and will go back to being 'stright'....


anyhows.. anyone with a little knowledge able to comment? me.. im bemused, it don;t take a lot but meh.. the bikes got 8,000 k's on it and has been ridden by a nannnnaa...

[merv]

I reckon Suzuki NZ are pulling your tit. If steel warps usually heat only makes it worse as in it relaxes and takes on that natural position anyway being the warped shape. Sounds to me like faulty from the start and they should replace them without argument.

[riffer]

Yeah, I agree with Merv. Sounds like dodgy rotors.

Make a warranty claim dude.

[cowpoos]

you buy the bike from colmans?

[Defiant]

I reckon Suzuki NZ are pulling your tit. If steel warps usually heat only makes it worse as in it relaxes and takes on that natural position anyway being the warped shape. Sounds to me like faulty from the start and they should replace them without argument.

I agree and have to say that I know that Suzuki a shitting you with that....I specialize in brakes and servicing on both cars and bikes we skim discs(cars only...lol.), cross drill etc, and i have come across almost every cause and case of damaged brake disc.......heat them up and they'll return to thier original shape my arse!!! They are either faulty or you've been hard arse on the brake with them.....Either way you can tell the cause in both cases.....call suzuki back they owe you some brake discs....:argh:

[Defiant]

get the shop to take em off and send them to me....i'll give you a written report of the cause if you like.....pm me..

[DEATH_INC.]

So anyways Suzuki NZ tell the shop that they can fix them easily enough.. by taking the bike out and heating up the brakes & rotors .. i.e ride the bike hard with the front brakes applied... as... and here's the punch line... the rotors/steel remember there original shape and will go back to being 'stright'....
Bwahahahaha :laugh: that's the funniest thing I've heard for a long time!!! :laugh:

[boomer]

hey guys,

yeah i got it from Colemans Poos. I'll take it in tomorrow(again) and let the bloke do his fango dango and watch him measure them afterwards. If they're still bent ( foookin unlikely that witch kraft will straighten 'em ) then i'll be in touch Defiant.

Cheers for the advise guys.. and i knew i'd be able to make you laugh! cos i did at the shop and matey boy took great offense :whistle:

apparantly they did put a claim in and suzuki told the shop .. rotors don't warp!

if i get no joy tomorrow i'll put it in writing to Suzuki and come have a chat Defiant.. cos the last thing i wanna do is fork out $800.


i'm still bemused.. Suzuki on one hand tellin me they don't warp and Colemans tellin me they are... ahhahahahahahah oh for a simple life:rockon:

[MSTRS]

Rotors will warp as aresult of (excessive) heat. If, like me, you have done a track day and just parked up after a session, the heat in the discs is retained in the caliper area and the uneven cooling of the disc will leave it warped. And no, they will not straighten of their own accord or by any other method.
This worked well enough for me... http://www.kiwibiker.co.nz/forums/showpost.php?p=1278044&postcount=2623

[MotoGirl]

apparantly they did put a claim in and suzuki told the shop .. rotors don't warp!


If I remember correctly, dad had warped rotors on his Busa about a year ago.

[boomer]

Ok.. so the bike went back today to get the black magic treatment. I asked how far out the rotors were and he said one was worse than the other but couldn't remember the figures.

I asked him to measure the tolerance before doing his stuff and then measure 'em afterwards.

The front wheel comes of and low and behold they're not out of tolerance, either of 'em. They were checked on the bike last time, not on a work bench. The head bearings needed a tweak and the pads got replaced and the front tyre was out of balance ... again.

So the bike actually stops now; I'll let ya know if i get more pulsing.


What a fiasco!!!


The tyre story...

A while ago, Ray Clees Dyno'd the bike and it nearly wrecked his machine as the rear was out of balance. It already had 80gms on it.

So back to cycletreads and they send the tyre to the distributor and ask for a refund. They say no. I lost my toys and cut a long story short, Cycletreads give me a new set of Pilot Powers 2ct's ( as well as the rear i wrecked over 3 weeks whilst they checked with the distributor )

Its this set of tyres that Colemans tell me are out of balance.... do i cry or laugh?!

[Defiant]

Geeeeeeeeze!!......what a drama.....are you sure the floor sweeper aint the one doing the checking......and the work.......you must have a realllllllllllllllllllllllllllllllllllllllllllllll llllllly long fuse.....keep us up to date this is gettin' an interestin' read....maybe after the tyres they'll say the chain is out of balance...ahahahaha........I sympathize with you boomer....no-one likes their ride of the road...

[Toast]

Rotors will warp as aresult of (excessive) heat. If, like me, you have done a track day and just parked up after a session, the heat in the discs is retained in the caliper area and the uneven cooling of the disc will leave it warped. And no, they will not straighten of their own accord or by any other method.
This worked well enough for me... http://www.kiwibiker.co.nz/forums/showpost.php?p=1278044&postcount=2623

While your logic is correct, I don't think that would be a common cause of the rotors warping, given that my race bike and many others in this country have done more track km's than Boomer's thou' and there seems to be very few complaints from racers of their discs getting warped from sitting hot after a session.

Having said that, I'm ultra anal and intentionally do very little braking on the cool down lap.

[Max Preload]

Rotors warp because they're held at elevated temperatures for periods and become annealed which allows the inherent internal stresses from post-casting casting forming and machining to warp the rotor.

[MSTRS]

While your logic is correct, I don't think that would be a common cause of the rotors warping, given that my race bike and many others in this country have done more track km's than Boomer's thou' and there seems to be very few complaints from racers of their discs getting warped from sitting hot after a session.

Having said that, I'm ultra anal and intentionally do very little braking on the cool down lap.

Precisely...trackdayers tend not to think of this (or get a warm-down lap)

[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]

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]

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]

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... :mellow: 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!

[codgyoleracer]

Interesting technique Maido, using a dial guage & "tapping the alloy carrier" at the high points can help also with straighting the discs - but it often doesnt last much more than a race or two. I have been told that Steve Bridge can press them straight on his machine in Hamilton (but have never used this service)
Glen

[Maido]

Interesting technique Maido, using a dial guage & "tapping the alloy carrier" at the high points can help also with straighting the discs - but it often doesnt last much more than a race or two. I have been told that Steve Bridge can press them straight on his machine in Hamilton (but have never used this service)
Glen


I got sick of them having to be tapped and adjusted after every race day, so removal of the rivets was the only way. it is failry common practice. next time you see a 250gp bike in the pits (if there are still some out there!) grab a hold of the disk and give it a shake, they are really really loose!

[Morcs]

Ah the joys of owning a suzuki..

bet ya never had this shit with ya CBR dunc?