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Discussion Starter #1
2004 ST4S ABS stock everything except a Dtimes cooling fan, and some dual compound Michelins.


Decided to tackle my moaning clutch today. Thanks to this forum taking it apart was a breeze!

As I have never seen the inside of a Duc dry clutch I would like to canvas the forum's opinion on its condition.

The steels all had some bluing; I will try and tackle those with some emory cloth.

The friction discs all had visible pads left. Most looked to be about the thickness of a piece of standard writing paper.

Lots of dust, that will be cleaned out tomorrow.

New 42t rear sprocket on its way with new chain (102 link) to help with the low gearing problem. Also new box of Cheerios to deal with the weight issue!


Cheers

Chris
 

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Realistically, not bad at all. Mine looked worse than that and worked just fine. The noise is annoying but generally harmless. 42T rear will help by a surprising amount - you're doing all the right things.
 

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If it's not slipping it's not too worn........

Cleaning out the dust will clear up the engagement moan...... for a while.

I hit my open clutch-covered clutch pack with the wash-wand at the car wash while cycling the clutch a few times with the engine at idle. That clears it up for about the same time period.
 

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The 42T rear sprocket should minimize if not eliminate the moaning. I went with a 42T rear sprocket at 6,000 miles on my late 04-ST4s and got 40,000 miles out of the OEM clutch.
 

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Looks in good shape from that angle/limited view which doesn't include the basket.
 

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Discussion Starter #6
Thanks a bunch guys! She goes back together today. Hopefully I'll get the new parts in next week.

So water intrusion into the clutch does not hurt it? I have always wondered about those very nice looking but open to the weather clutch covers.


Cheers

Chris
 

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Your clutch looks fine. Be sure to put the plates back together the same sequence they were in when you removed them.

Water can cause problems for your clutch. The plates can stick together and refuse to engage. Therefore, always run the bike after getting the clutch wet. I would not intentionally run water from a car wash into my clutch. A shot of compressed air and brake cleaner works well (apply while engine is turning). Wear a dust mask and gloves when you blow dust around.

Two things to look for to determine clutch wear are thickness of the total pack measured with a caliper (I don't remember the spec at the moment but you can find it here by doing a search) and the space between the tangs and the basket. The tangs and the basket sometimes beat each other up well before the friction material is worn away. The clutch still functions but is noisy as hell.

Replacement clutch packs and baskets are available that eliminate "moan" and reduce clatter.

Jeff, Snowmass Village
 

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42 will be a great improvement. Ive had so much drama with my clutch moaning etc. Did the quite clutch mod 5000kms ago. This weekend is the first time i have had a passenger on for 300kms.

To my amazement..no groaning like I had anticipated. Haven't cleaned it out for a while but the clutch seems to work better with age!!
 

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Well she went back together just fine. I started the bike and was amazed at how quiet the clutch was, then I realized the pack had not been cycled so I used the clutch a few times and restored my rattle. Not as loud as I remember but still there.

Attached a few pics for those asking about the basket. Also a before and after pic of the plates.

For those interested in such things. Min thickness of a clutch plate is 2.8mm, max allowable warpage is .2mm.

Minimum spring height (uncompressed) 36.5mm

Maximum gap between a clutch tang and corresponding basket notch is .6mm.

Cheers

Chris
 

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Chris,

My basket does not have as deep a slots as yours and my friction plates have no evidence of burring on the tangs but I have bang on the 0.6mm clearance. I have always been puzzled by this as they have had this clearance from almost new??

Anyhow glad to see you are back together and running fine. There really is nothing to pulling the dry clutch apart cleaning/maintaining the unit as you have found out....
 

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I too thought it was a strange measurement. If the clutch tang has worn any type of slot into the basket notch then is that the clearance you measure and if so where do you find such a tiny tiny tiny feller gauge? :)

This is my week off so I am taking her for a short (2 hour) ride today.

Cheers

Chris
 

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Mine measures 0.6 between the original basket (unworn part) and the plates which also looked new......strange but as long as she rides ok I'm not going to worry.
I have never seen anyone trying toi measure betwen the plate and the bottom of the worn part of the basket. I think its really just measuring the wear on the friction plates.??

I'll slowly save my pennies to buy a new clutch complete one day. By the time I have saved enough, the original will be shot!
 

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Aha! now theres a thought. Would add a bit of life to the clutch............
 

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did you have a look at the pressure plate where the springs sit in the bottom of the spring well? my bike was a nyc unit with 4100 miles and when i took the clutch down to do the quiet mod i found the tabs worn out of spec and daylight showing at the bottom of the pressure plate spring wells. could be a condition caused by a side load applied by the springs?
 

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That is a real good question! My tabs were OK but I too had small holes in each of the spring seats. Only one seat didn't have it but you could see where it would show up if it did. To me it looked like the holes were supposed to be there and the one seat that didn't have one was just a bit of casting flash covering it up.

All of that is a guess, anyone know for sure?

Cheers


Chris
 

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OK, cool but 25% of what? Are there supposed to be holes?

Cheers

Chris
 

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lt's book just shows a picture of a pressure plate with daylight showing in the spring wells. the 25% can be of the circumference or 360 degrees, depending on how make the measurement.
 

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Good thread guys,

I am starting to understand our fickle clutches a little better now, and understand how & why the "quiet mod", might work.

My ST2 is up for its 30,000kms service next week & my clutch noise turns heads from blocks away, it is as loud as hell.

Upon inspection, my clutch basket shows the most amount of wear, caused by the plates bashing crap out of them.

So, it makes sense to me to add another plate or two to the bottom of the pack to raise the stack in the basket to bash against the unworn high spots in the basket, thus reducing the noise, hopefully?:cool:

I will do a photo shoot of the job on the weekend, I am planning to undress her, ready for her service next week, to save some labour time off the service costs.

Craig
 
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