Burnt clutch? And best replacement for racing application?

[Toast]

Hi all

The symptom is this: Give it heaps of throttle and revs and all you get is revs and not a lot of forward motion. From memory it was worse in the higher gears too.

A 'burnt'/slipping clutch seems the most obvious cause from my very limited knowledge…is there anything else this could be?

If replacing the clutch is the option…what’s the best? OEM, or I saw on eBay a ‘Barnett Kevlar Clutch Kit’. Would something like that be better for a race application?

Price from Yamaha shop lies somewhere between steep and horrendous so unfortunately eBay I think it will have to be.

Cheers for any help!

[Shaun]

Hi all

The symptom is this: Give it heaps of throttle and revs and all you get is revs and not a lot of forward motion. From memory it was worse in the higher gears too.

A 'burnt'/slipping clutch seems the most obvious cause from my very limited knowledge…is there anything else this could be?

If replacing the clutch is the option…what’s the best? OEM, or I saw on eBay a ‘Barnett Kevlar Clutch Kit’. Would something like that be better for a race application?

Price from Yamaha shop lies somewhere between steep and horrendous so unfortunately eBay I think it will have to be.

Cheers for any help!


What make and model bike! Tech, for NZ Champs, it should be a std clutch!!

[Toast]

What make and model bike! Tech, for NZ Champs, it should be a std clutch!!

Hey Shaun

Bike is an 07 R6

Sports Production regulations state:

"3-24 Clutch
Only friction and drive discs may be changed, but their number must remain as original.
Clutch springs may be changed."

So I wouldn't have thought that excluded aftermarket kits potentially of a different material...unless there is something elsewhere in the rules that changes this?

I've been reading up on the WERA forums though and the general consensus thus far seems to say go OEM, so I guess I will aim for that.

[WarrenW]

Hi,

I fitted a Barnett to my TL1000s for street use and had an immediate improvement for slippage. It was bucket loads cheaper than an original and I think it works a lot better.

Just my 2c worth.

[KS34]

I have had something similar on an 06 GSXR 750, but all it needed was an adjustment. On the gixer there is a bolt/cover you undo on the side casing which reveals the screw and nut adjuster. Not sure if the R6 has something similar.

[NinjaBoy]

Toast, surely all you need is to replace the fibre plates but you won't know that until you open it up. The fibres should be fairly cheap...

[Chrislost]

Are EBC kevlar friction plates any good they are the only ones i could find this side of PMCC for my bike. Probably can find them for yours too.
Guess i will find out on teh 1st.
Has anyone had good or bad experiences with them?

[steveyb]

Barnett make all clutch parts and they are of higher quality (generally) than OEM.
So you can use any manufacturers parts as long as you don't change the type of clutch, eg put in a slipper when the bike does not have a slipper.
EBay is the place, esp with the hole the USD is going down right now.

[Toast]

Barnett make all clutch parts and they are of higher quality (generally) than OEM.
So you can use any manufacturers parts as long as you don't change the type of clutch, eg put in a slipper when the bike does not have a slipper.
EBay is the place, esp with the hole the USD is going down right now.

After reading on the WERA forums over the past couple of days I've been put off Barnett stuff...something about the plates shearing and dumping crap in to your oil and destroying motors...

Not saying that one should believe all they hear on the internet, but there did seem to be more than one case of it happening.

But yeah, great buying from the US right now!!!

[Toast]

I have had something similar on an 06 GSXR 750, but all it needed was an adjustment. On the gixer there is a bolt/cover you undo on the side casing which reveals the screw and nut adjuster. Not sure if the R6 has something similar.

Hmmn, nah, it didn't really seem to have anything like this. The only reference to adjustment that I could find in the manual involved changing the first or second plate in the stack to adjust the thickness of the total stack.


Toast, surely all you need is to replace the fibre plates but you won't know that until you open it up. The fibres should be fairly cheap...

Even the fibres were over $300 for the set from Yamaha in NZ

I opened it up last night and all of the fibres seemed to be within spec (minimum was 1.8mm, they were all about 1.94mm. The whole stack was within spec also.

The steel plates all seemed a bit scorched and blued. The manual says warpage limit is 0.10mm, which I don't really know how to measure so accurately, but it does look to me like there could be some warpage just from placing them flat against the garage floor.

The springs also seemed to be below minimum length at 53.8mm or so (min. 54mm), but I'm not sure that the ones in there are the standard ones or not. Would this be a cause of the slipping?

[FROSTY]

Dude give Stranger a yeodle. He went through this same shit with a gixxer thou K3. I think he got down to 2000 grit paper on a sheet of glass to get the clutch back n operation.

[vtec]

Yeah mate sounds like your springs are screwed. Also, if you can see warpage against a flat surface I would look at changing the flat plates too.

I just swapped a clutch out of my spare VFR400R into my road/race one, and was great to compare the difference between the two sets of flat plates and pad plates. It's now working a treat.

I would suggest getting a whole new kit.

http://www.nwa.co.nz/product_detail.php?P_ID=349
http://www.ebcbrakes.com/Assets/EBC2009intlmccatclutches.xls

I'm looking at their discs, cause I've had 3 warped sets of front discs on my VFR really starting to piss me off.

[Sparky Bills]

Shoulda bought a honda... :innocent:

[Toast]

Shoulda bought a honda... :innocent:

:2guns:

hahaha...that actually did cross my mind...but nah, the yammy is gonna be my new best mate once we get this out of the way :D

[k14]

:2guns:

hahaha...that actually did cross my mind...but nah, the yammy is gonna be my new best mate once we get this out of the way :D
Have you given dave cole a call? He would probably know a bit about those engines :)

[Toast]

He built this one, actually :) I don't really want to bother him when I won't be giving him any business for his trouble, so plan is just to replace plates, fibres, springs and fingers crossed it should be all good!

[FROSTY]

He built this one, actually :) I don't really want to bother him when I won't be giving him any business for his trouble, so plan is just to replace plates, fibres, springs and fingers crossed it should be all good!+
mate Dave is a f$$$ great guy. One of the real gentlemen of our sport. Give him a yeodle

[Toast]

So...got the new clutch plates and fibres in the mail yesterday...but some of the plates have corrosion on them...is still ok to use them? I assume it would be necessary to get some sand paper and remove it first? Would you have to be careful to not be too vigorous and change the texture of the plate?

[Sketchy_Racer]

I would think that a quick rub with a scotch brite would be sweet, you just want to remove the surface rust, don't worry about scrubbing out the marks.