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Remove the cushion spring from factory clutch pack?
Posted: Sun Jul 17, 2011 10:50 pm
by bluesbreaker45
Well guys,
For the 2nd time now an EBC SRK clutch pack has failed me (clutch fiber plates exploded and came out in many pieces). Both with less than 1500 miles!!!
I have decided to just replace with OEM. I've done some research about using the OEM clutch pack and it seems the concensus view is to remove the cushion spring and the associated fiber plate and replace with a friction plate of normal thickness.
http://www.cyclepartswarehouse.com/fich ... 4&fveh=591
This mocrofiche says I need:
8 of part #6 which are the steels
7 of part #7 which I suppose are the regular fiber plates
1 of part #8 which appears to be a fiber plate (unique?)
1 of part #12 which appears to be a fiber plate (unique?)
Can you guys give me some clarification on which parts to buy and which to omit?
~Zack
Re: Remove the cushion spring from factory clutch pack?
Posted: Sun Jul 17, 2011 11:59 pm
by DonTZ125
We've had this discussion a few times over on the Archives recently; these were my comments:
The idea behind the narrower (radial cross-section; same axial thickness) fiber and wave spring (pushing the adjacent steels APART) with the smaller bikes was (IMHO) to reduce the clutch spring squeeze for easier feathering and modulation; a lot of the little sport bikes had fairly tall gearing. It was far easier to do this than to redesign and remanufacture the clutch hubs and spring towers for reduced compression, as well as far cheaper to retro-fit this upgrade (and it IS an upgrade, for those bikes that benefit from it).
I would suggest for the 1ks that this is not only unnecessary, it's actually counter-productive, as these bikes are known for slipping and eventually grenading their clutches. Removing the modified fiber and wave spring is literally as easy as, well, removing the modified fiber plate and wave spring, and replacing it with a standard 'mid-pack' fiber plate.
The fact that members on this board have reported catastrophic failures of this modified plate just emphasizes that this was a Bad Idea ™.
and
QUOTE (1990fzr1000 @ Jun 25 2011, 10:37 AM) *
i took mine out the first year i had my bike... which maybe why i never had a clutch basket problem all these years smile.gif i was told that its in there to help the clutch pack separate and allow for a smoother engagement...... so i took it out to help lock up the clutch more wink.gif
While the point behind the exercise is to improve feel and engagement, the method chosen to do so is to weaken the clutch. This works fine with the smaller bikes with over-powered clutches. On the FZR1000 it very likely leads to slip and chatter, and may very well be the culprit behind the notoriously fragile baskets. Slip and chatter hammers on the fingers, leading to fatigue, cracking and fracture.
I think a better approach to the problem (if any) of lever force would be to change the clutch master cylinder to something more appropriate (no suggestion).
I think the most telling condemnation of this arrangement is that they stopped doing it - the '93+ FZR1000s didn't have the wave spring and modified clutch plate. The guys at Yamaha had some pretty good ideas over the years; unfortunately, they also had a few wall-bangers, and I think this is one of them ...
Unless they're damaged or warped, you probably don't need to replace the steels. Wipe them reasonably clean, stack just the steels together, then try to look through the stack while twisting them like you're cracking a safe. If at any point you see daylight, replace the set.
The frictions you see are what you want; it's not unheard of for the first and last friction to be a slightly different thickness. According to your link, you want:
- 8x 4H7-16321-02-00 (#7 & #8; note that they now use the same p/n!)
1x 3GM-16321-00-00 (#12)
cheers,
Don
Re: Remove the cushion spring from factory clutch pack?
Posted: Mon Jul 18, 2011 9:06 am
by bluesbreaker45
Don,
I had read your posts on fzr archives before and I believe what you say about the cushion spring and associated fiber makes good, good sense.
Thank you very kindly for clarifying that for me.
~Zack