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K5/6 Clutch Setup and improvement

23019 Views 77 Replies 36 Participants Last post by  wsmc99
There has been a lot of talk about the K5/6 clutch and it's adjustment etc.

Well I have a K5 clutch in my K2 and I've been doing some testing and adjusting and come up with a pretty sweet setup.

Keep in mind all this testing is done on the road with all kinds of riding in mind.

Where do I start ?

The stock clutch runs very dry.

The first thing I did was to add the 3 extra holes to the clutch basket.

The next thing was to grease the ramps on the lifters

The stock clutch springs are a little soft. They let the clutch slip a little too easy and if you make a bit more power (180 plus at the back) then they can even let the clutch slip under hard acceleration.

I changed the stock clutch springs for Barnett ones. I believe they are approx 15% stiffer. They feel about 15% stiffer on the clutch lever too.

I also noticed while I was at it that the top of the clutch spring is not held straight in it's hole so it flings out and rubs on the clutch hat. I had some custom washers made to retain them straight. ( made by - mperacingonline - with some www. and a .com)

The stock clutch comes with 2 "reaction washers". These are the cone sahped ones with all the fingers on them. Each stock spring provides 225N of spring pressure.
The stock setup is therefore 450N. I read soemwhere that Yoshimura use more like 675N. This is 3 stock springs. (there is a Yoshi kit available with 150N and 300N springs for more tunning)
So I bought a 3rd reaction spring and fitted it too.

Then I adjusted the lift pins , turn them in till they bottom, turn them out 2 and 1/4 turns and lock up the nut.

On the road then the clutch is a little heavier than stock but not a heavy clutch. When you change down gears it's still really smooth when you let the clutch out and the slipper still works but with some engine braking.

It will still never lock the back wheel and is silky smooth.

The only other adjustment to watch is the push piece. You need to make sure there is some room for it to move before it pushes the clutch hat or it can keep the clutch partly unloaded.

This is the adjustment most people are concentrating on but if you don't get the lift pins right you could wear the clutch out pretty quick and have it bottoming on the push piece again in no time.

I guess what I'm saying is... it's a package deal.

Get the whole package right and it's a really sweet setup.

Hope this helps someone and the pics show what I'm trying to describe...
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Cool post, Stocky. Thanks for sharing. Can you also post up the dimensions (inner and outer diameters (plus width) of the custom washers (3rd pic)? I'm going with the Yosh spring kit, and may as well make up a set of spring guide washers as well.
Excellent Article +1 Reputation
Throttlestop said:
Cool post, Stocky. Thanks for sharing. Can you also post up the dimensions (inner and outer diameters (plus width) of the custom washers (3rd pic)? I'm going with the Yosh spring kit, and may as well make up a set of spring guide washers as well.
Excellent post as always Stocky.

I am also very interested in the dimensions on the washers.

BTW, do you know if you can use a K2 clutch cover gasket on the K5 and whats the trick of pulling the clucth basket without the special tool mentioned in the manual?

Me and mechanical stuff .............I'm so lost sometimes :eek:
Can you illustrate where the extra holes are drilled?
The pic below shows the basket (sorry about the quality)

3 of the little holes are stock, the other 3 have a casting mark showing you where to put them (It'll make sense when you are looking)

A rattle gun undoes the nut without having to hold the basket (you do need to pry the dinted over lock nut out first and dint it back in when reinstalling)

Yes I am pretty sure the K2 gasket will fit. The only change to the clutch cover was to the middle for the adjustment hole.

And the other pic is dimensions of the washer to retain the spring.
Thanks, Stocky.
Thanks Stocky,

I have one question,

The K5 manual shows that there is 3 reaction springs as stock? You mention that you have 2, can you confirm. I am also looking at the Yoshi website and under the reaction spring page it says [Standard Force:225N (1 Plate) x 3 = 675N]

So it looks like 675 N is the standard setting with 3 plates.

Yoshi suggest between 450N and 900N. So if I want to try 450N (more slip) can I just use 2 standard springs or do I need three of the yoshi 150N springs to keep the same thickness of springs?

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Also stock one other question. With the lift pins you mentioned to turn them all the way in and then back them out 2 1/4 turns. I take it this is with the clutch installed? The manual says to make them 0.2-0.4mm sticking out the back of the clutch, how much does 2 1/4 turns equate to?

Yes the manual suggests that there is 3 reaction springs but in reality I've only ever seen 2 in there.

Also the parts diagrams suggest 2 in a K5 and 3 in a K6 but the K6 seems to have 2 as well.

Yes you fully assemble the clutch, then turn the lift pins in till they bottom then back out 2 and 1/4 turns and lock them off.
Hey Stocky. Its mato from OSB. I live in R'Ton after I have my dynojet and maybe some other little goodies installed and tuned if my clutch doesnt work as well as it should would you mind if I contracted you for such job. Ill do all the hastles of aquiring all parts need then I can just let you do the tricky bits and you charge what you want for it? Let me know if you interested in such work first and Ill let you know whether it needs it after I finished my tuning. I realise it might be a pain in the arse so I wont be offended in the least if your not interested.
Thanks Stocky,

I feel there is still something wrong with the Yoshi info or your info though. On the Yoshi site it says standard is 3 springs for 675N and the Yoshi springs allow between 450N and 900N.

If there is only 2 springs and they are 225N each then the standard force of the springs is 450N which means if you buy the Yoshi reaction spring set there is no further adjustment to get more slip only to get more engine braking because the minimum they suggest is 450N. I can't believe that is the case? How else can you get more slip?

Is there someone we can check with? Do the Yoshi importers know or are they just salesman?

Microfiche is wrong, there are definitely 3 225N springs in there standard.
Thanks for the excellent write up. Are any special tools needed to do this mod?
The Yoshi kit comes with 3 springs at 150N and 3 with 300

Between the stock 225N ones and the yoshi ones you can make any combo you like (suggested between 450 and 900N)

I ran 450 for a while and I can't imagine anyone wanting more slip than that , the clutch slipped very easy.

You also have to remeber that Yoshi are suggesting for track use not road use so the clutch will want to be a little stiffer.

I'm running 3 reaction springs and 15% more clutch spring and it's pretty good. I hope Suzuki have got 3 in the newer bikes.

Mato, if you need help with anything or want the things you have bought setup then I'm happy to give you a hand.

PM me.
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Here is an example ..... K5 clutch and K6 CLutch

(Part number 17 is the reaction spring)
miller said:
Microfiche is wrong, there are definitely 3 225N springs in there standard.
Like I said before.

My K5 which I bought new had 3.
I'm not saying they all have 2 or all have 3.

But, if your clutch is real soft and slips real easy, you might have 2
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