• 4 Stroke Husqvarna Motorcycles Made In Italy - About 1989 to 2014
     TE = 4st Enduro & TC = 4st Cross

  • Hi everyone,

    As you all know, Coffee (Dean) passed away a couple of years ago. I am Dean's ex-wife's husband and happen to have spent my career in tech. Over the years, I occasionally helped Dean with various tech issues.

    When he passed, I worked with his kids to gather the necessary credentials to keep this site running. Since then (and for however long they worked with Coffee), Woodschick and Dirtdame have been maintaining the site and covering the costs. Without their hard work and financial support, CafeHusky would have been lost.

    Over the past couple of weeks, I’ve been working to migrate the site to a free cloud compute instance so that Woodschick and Dirtdame no longer have to fund it. At the same time, I’ve updated the site to a current version of XenForo (the discussion software it runs on). The previous version was outdated and no longer supported.

    Unfortunately, the new software version doesn’t support importing the old site’s styles, so for now, you’ll see the XenForo default style. This may change over time.

    Coffee didn’t document the work he did on the site, so I’ve been digging through the old setup to understand how everything was running. There may still be things I’ve missed. One known issue is that email functionality is not yet working on the new site, but I hope to resolve this over time.

    Thanks for your patience and support!

Clutch slips after 7602 slave piston install.

MorrisBetter

MorrisBetter

Husqvarna
AA Class
I installed the 7602 slave piston and now the clutch slips under heavy load. The lever feels normal, but the clutch disengages with less lever travel.

Any ideas?
 
Found this over at supermotojunkie.com. The piston I got from 7602 is anodized black. Has anybody here heard of this problem?

http://www.supermotojunkie.com/show...10-SMR-clutch-slipping-what-is-the-cause-Help!

I reinstalled the stock piston and the clutch is working normally again.

I can see that air is getting into the system at the slave. I put a chunk of clear plastic tubing on the slave bleeder nipple and filled it with Magura Blood, and after a few cycles of the clutch I see air bubbles come out of the slave when I open the bleeder.
 
OK, here's what is going on. The stock piston when fully compressed is .291" from the outside edge of the snap-ring. The 7602 piston when compressed will only go in .208". That's .083 difference in total travel. The difference between the thickness of the pistons is; .267 for the 7602, and .186 for the stock piston (.083 difference). Hmmmmm....

What this means is the 7602 piston is not allowing the pressure plate to return to a fully compressed position. This piston may work with a brand new set of clutch plates, but as the clutch wears, the actuator rod between the slave and the clutch moves left. The limited travel of the thicker piston just doesn't allow the rod and pressure plate to move enough for the clutch to fully engage.
 
Good find. What's next? Contact 7602 To find out why the Piston is shorter? I can't imagine theirs anything you can add to reduce the clearance without scuffing the bore.
 
JasonfromMN said:
Good find. What's next? Contact 7602 To find out why the Piston is shorter? I can't imagine theirs anything you can add to reduce the clearance without scuffing the bore.
Click to expand...

The 7602 piston is thicker to keep it straight in the bore. The stock piston tends to rock in the bore and causes wear to the anodizing, and eventually it fails to seal.

I talked to 7602 today, and apparently a few others have had this same problem. 7602 suggested that I shorten the actuator rod that goes between the slave and the pressure-plate by filing the end off. I think that would work, but as the clutch continues to wear, the rod will eventually be too long again, and of course I'd probably be 50 miles into the thicket when it happened. I could just take off the .080 difference, and it should effectively be the same as the stock setup. The problem there is that it may be too short to work with a fresh set of friction plates. Seems like a kludge fix....

In any case, I'd feel a lot better about this solution if I knew exactly why I'm seeing the problem and most other riders don't. Is the rod longer than it should be? Is my clutch worn to the point that I should replace the friction plates? Maybe I should just throw in a new set of pates and see what happens? I have 5000 miles on the bike, and I have de-glazed the plates two times, so that may be a prudent move.

Maybe I should call Zip-ty and see if their slave housing is deeper than stock?

I think I'll just buy a new stock slave and go ride.
 
This happened to our TXC 450 as well after installing the 7602 piston. Shaved about .06 off at the suggestion of 7602 and then it felt normal again (after quite a bit of back bleeding from the bottom, standard mineral oil). That was in January, I believe, and it hasn't noticeably changed in the meantime.
 
I would go ahead and trim it down .6-.8" like has benn suggested and you will be back to the original relationship.
There are specs that include wear limits in the owners manual for the clutch plate thickness.
 
Phoenix said:
This happened to our TXC 450 as well after installing the 7602 piston. Shaved about .06 off at the suggestion of 7602 and then it felt normal again (after quite a bit of back bleeding from the bottom, standard mineral oil). That was in January, I believe, and it hasn't noticeably changed in the meantime.
Click to expand...

I assume you shortened the clutch end of the rod?
 
Xcuvator said:
I would go ahead and trim it down .6-.8" like has benn suggested and you will be back to the original relationship.
There are specs that include wear limits in the owners manual for the clutch plate thickness.
Click to expand...

I think I'm just going to start with new plates and see how much the rod moves. I'll adjust the rod length from there.
 
Epilog...

OK, I put the 7602 piston into a new slave housing, installed a new clutch stack, and shortened the actuator rod by .040". The clutch feels perfect.

The old stack was .050 shorter than the new stack, so there was some wear, but not a lot. When installing the new slave, there was a significant amount of compression of the slave piston as I tightened the housing down. This tells me that I can take more off of the rod and not risk making it too short for a new clutch.

The slave / clutch swap was very simple. This bike is so easy to work on. I've yet to have one of those, "Why did they design it this way?", moments. Most bikes I have owned are just difficult to wrench on. This one keeps being a pleasant surprise every time I take a wrench to it.
 
OK, I put the 7602 piston into a new slave housing, installed a new clutch stack, and shortened the actuator rod by .040". The clutch feels perfect.

The old stack was .050 shorter than the new stack, so there was some wear, but not a lot. When installing the new slave, there was a significant
amount of compression of the slave piston as I tightened the housing down. This tells me that I can take more off of the rod and not risk making it too short for a new clutch.
Click to expand...

Glad you got it figured out. I apologize that you had problems with getting it set up, but everything should be good going forward.

This bike is so easy to work on. I've yet to have one of those, "Why did they design it this way?",
Click to expand...

I agree, Husky seems to know that dirt bikes are gonna break down from time to time and they should be designed to be easily fixed. I have however come across several of those "why did they do it like this" areas.
 
You must log in or register to reply here.
Back
Top