ZR750 C1 Clutch basket rubber dampers

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ZR750 C1 Clutch basket rubber dampers

Postby 71 V12 » 28 Jul 2018, 15:55

Hello all,

I recall a post advising a source of clutch basket rubber dampers, searched but I can’t find the post now.

I think the source was in the US, can anyone confirm?

Many thanks,

Kevin
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Re: ZR750 C1 Clutch basket rubber dampers

Postby David Richard » 28 Jul 2018, 16:40

hi yes that was me in September ,look under wanted and you will find info about 750 clutch dampers ,the chap turbo steve is very helpful and quick to post ,david
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Re: ZR750 C1 Clutch basket rubber dampers

Postby 71 V12 » 29 Jul 2018, 10:29

Hi David,

Thanks for pointing me in the right direction.

I have emailed Steve for a quote on the parts.

Cheers,

Kevin
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Re: ZR750 C1 Clutch basket rubber dampers

Postby Larry02ACR » 29 Jul 2018, 15:31

He's now doing 550 dampers as well.
- Larry
1990 Zephyr 550, 1978 KZ400, 2004 KX250
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Re: ZR750 C1 Clutch basket rubber dampers

Postby Freddy » 30 Jul 2018, 09:25

71 V12 wrote:Hi David,

Thanks for pointing me in the right direction.

I have emailed Steve for a quote on the parts.

Cheers,

Kevin


Certainly worth doing. I decided to buy a complete new clutch basket, and the difference in the 'clunkness' of the gearbox is MASSIVE. With new rubbers the gearbox is as slick as any brand new modern bike, with loose time hardened rubbers, unless you tried really hard nearly impossible to shift in up the lower gear without a massive CLUNK.

I also bought some clutch rubbers of Steve to recondition the old one just to have a spare on hand. Rubbers arrived promptly. Haven't got around to doing the job, one day.
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Re: ZR750 C1 Clutch basket rubber dampers

Postby ZR468 » 01 Aug 2018, 01:18

Sorry, I am inexperienced in this. What does the clutch basket dampener do?
I keep shifting into neutral when I go from 1st to 2nd, sometimes even 3rd to 4th. Would this damper help?
Also my clutch feels a bit snatchy, kind of on and off without much friction zone. Is it a symptom of something wearing out or getting old?
Kenny
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Re: ZR750 C1 Clutch basket rubber dampers

Postby Turbosteve » 01 Aug 2018, 03:11

The dampers cushion the clutch basket as you shift from gear to gear to make shifting smoother.

Some manufacturers use metal springs to accomplish the same thing. Kawasaki uses six rubber dampers on the 550 - 750 models -- and maybe other models that I'm not familiar with.

Problems arise with age and mileage. The rubber hardens, shrinks, and eventually breaks down and the dampers literally disintegrate. How do you know if your dampers are toast? If you find small particles of rubber in your oil during a change that's a sure sign that your dampers are breaking apart.

1980-01-01 00.00.35.jpg
Worst case scenario, but you get the picture.


Dampers are not a replaceable item. They come together with the clutch basket as a single unit -- but Kawasaki no longer manufactures the baskets. So the only cure is to remove the backing plate from the clutch basket and replace the dampers with aftermarket parts. Some owners think they can get around the problem by purchasing a used clutch basket from a salvage yard or eBay. What they're really buying is time, and not much of it, as the problem is mostly related to age.
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Re: ZR750 C1 Clutch basket rubber dampers

Postby Freddy » 01 Aug 2018, 03:21

ZR468 wrote:Sorry, I am inexperienced in this. What does the clutch basket dampener do?
I keep shifting into neutral when I go from 1st to 2nd, sometimes even 3rd to 4th. Would this damper help?
Also my clutch feels a bit snatchy, kind of on and off without much friction zone. Is it a symptom of something wearing out or getting old?
Kenny


Perhaps the easiest way to understand what the clutch dampeners do is to examine a typical car clutch plate. Note the 4 springs in the center hub. The inner and outer sections of the car clutch plate are not rigidly fixed together, but can rotate slightly against each other restricted in that movement by the tension of the 4 coil springs. This controlled movement gives some 'flex' and so a smoother take-up of the clutch when the pressure plate grips the outer friction surface.

The rubber clutch dampeners in a motorcycle do essentially the exact same job as those metal springs in a car clutch plate. Because motorcycles for space reasons use narrow multi-plate clutchs the car design would't work, so rubber 'springs' are use to tension the inner and outer hubs of the 'clutch basket'

Image

The problem with using rubber springs (that'd really what they are) instead of metal springs is that the rubber goes hard and looses tension with age. There isn't even a question of whether or not the rubbers in a Zephyr 750 clutch are still serviceable. Unless they have been replaced at some point, the answer is they will be shot.

So the answer to will replacing the rubbers (or the expensive alternative, a complete new clutch basket) help rectify your problems, the answer is yes. The gearbox will tighten right up, clunks will disappear, and it'll be much smoother. You can still find false neutrals if your lazy with your changes, but that's a different matter.

And don't think a second-hand unit is a solution of itself. The rubbers in it will also be shot. About all this approach is good for is if you can source a second-hand one cheap enough it will allow you to recondition it at your leisure and then you just do a complete clutch basket swap, making the actual time the bike is off the road about 1 hour.

P.S. To dismantle and reassemble a clutch on a Zephyr 750 is a quite an easy job for someone of moderate mechanical ability. I'm not talking about reconditioning the clutch-basket, just the dismantling and reassembly of components. But you do need a special tool to hold the clutch basket. EBC sell them and they are not that expensive. You'll also need a quality larger size torque wrench. The large nut that hold the clutch basket on is a 'crush' style and should be replaced every time it is undone.

Just carefully keep the parts in order during dismantling, and put them back together in the same order, and you basically can't go wrong. Quite straightforward with the only couple tricks probably being disconnecting the clutch cable, and knowing to swing the arm the clutch cable attaches to fully counter-clockwise to disengage it before removing the cover.
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Re: ZR750 C1 Clutch basket rubber dampers

Postby ZR468 » 01 Aug 2018, 16:13

Gentlemen, thank you for the detailed explanations. Learnt something new today, but I think I'll leave well enough alone for now. If it is nor broken, don't fix it.
Kenny
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Re: ZR750 C1 Clutch basket rubber dampers

Postby ZR468 » 01 Aug 2018, 16:41

My curiosity got the better of me, so I started checking out the clutch parts prices online. Attached is the clutch diagram, which piece is the clutch basket and which is the dampener? Thanks.
When I replaced the rear tire hub dampener, the improvement was dramatic. I presume replacing the clutch basket dampener would have similar results.
Kenny
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