2 warped clutches in 1 day?

[FatDogX]

As of right now it is looking like it's the clutch post, but who knows. The sled I was riding was a demo sled from a friend of mine's dealership. The sled is back there and they will be pulling it apart. Not sure to what extent they will "inspect and investigate" as it's covered under warranty. I wish I could tell you more, but as I find out, I will definitely pass the info along.

Personally, I would like to know for sure or at least a very educated guess as to what actually happened.

I know that the other sled was bone stock and nothing was ever opened up on the clutch before that day, so the "over torque" suggestion would be less of a possibility.

Great info from everyone, definitely keep the thoughts coming and I hope this is a VERY RARE issue that we won't see for a long time!!

Same clutch bolt and clutch with different taper on the 900's torqued to 96 ft lbs. Lots more heat in the primary often and not really an issue.

Anything is possible though.

Fatdog and Sledmax... did you verify if the problem is in the spider or the clutch post?

Pull the spider and on them, put the cover back on with the bolts and see if the clutch moves freely.

That will tell you if it is the shaft or the spider sliders/towers that are sticking.

MH

 

[motodad383]

had a similar situation on an 06 600. moveable sheave got sticky after overheating the clutch. put in new bushing and it cured it. but through that experiece I started using a brake cylinder hone on the moveable sheave and cover bushings before washing my clutch pieces. It gets dust/dirt/goo loosened up.

It works for me

 

[2007dragonman]

sled clutch

and to add yes we have seen some that the bushings fixed them, one we had tried the bushing alone without the sheave and would not even slide onto the shaft, put in new clutch and all was good to go.

definately not a huge problem just seen a few.

 

[FatDogX]

Spoke with the dealer reference the one I was riding and their not going to mess around with trying to diagnose or fix the clutch, there just going to warranty the clutch and replace it entirely.

Probably the best thing to do for the long run, but it would be nice to know exactly what happened.

 

[Boston Racing]

Excessive heat in the clutches will cause the aluminum face of the clutch to expand enough to crush the bushing inward reducing clearance and causing the the movable shieve to stick.

I have had this happen on 2 of my old sleds and always ended up buying a new clutch because our dealer said they warped. If the aluminum face expands causing the bind will replacing the bushing fix them usually?

 

[Teth-Air]

13 Pro RMK 800

So here is what happened to my clutch on my 13 when I tried to pull it for the first time.

The dealer could not get the back half off, even by cutting it so I am wondering if it spun causing the extra heat like in your case?

They are installing a new crank under warranty.

 

[yz400ex]

I had this happen 2 seasons ago. Once we got back, the clutch was pulled and examined and the bushing in the moveable sheave had kicked sideways a little, causing the clutch not to disengage all the way. Was a pain to get out of the back country.. starting it was like starting a car in first gear w/no clutch.. pull the rope and it would just take off cuz the clutch was always partially engaged.. We replaced the moveable sheave and never had another issue.

 

[TRS]

On a problem clutch. Has anyone measured the width of the spider, at the buttons, and tower width measurements at each end of travel?

 

[LoudHandle]

Funny this subject came back up. Had a Dragon do this last weekend. Tried everything to get it to loosen up, short of full disassembly. My best guess is that it was over torqued when the stealer ship put a fix it kit in. As the clutch bolt was WAY too tight! And bent a cork screw into my puller trying to get it to pop off the crank. Ended up hydraulic'ing it off with acetone and electrical tape on the puller threads.

My thoughts are; stealership used an impact to install and then every time the clutch got heat soaked it expanded and slid up the taper abit. Expanding the clutch hub ever so slightly in the process. Leading to the movable sheeve sticking and not returning to fully open. No visible defects on clutch shaft and no binding at spider or cover bushing. It was pretty dirty but even after a through cleaning with acetone it was still sticky for the last ~3/8". I installed a new spare I had so he could finish out our season and will be sending it out to Indy Dan for his diagnosis and to work his magic on.

This seems the most plausible explaination to me for a couple of reasons; one the move from the 30 mm taper of old to the new 32mm. Leaving a lot less meat in the clutch hub. This thinner wall on the hub means the thermal gain is not conducted away as fast as the clutches of old and are more sensitive to proper torque, balance, and crank runout. The 30 mm of old you could over torque, heat soak, and were much more tolerant of run out. I believe that is also why the newer 32 mm clutches are breaking off right where the crank snout ends. All good points to keep in mind.

 

[tdbaugha]

My thoughts are; stealership used an impact to install and then every time the clutch got heat soaked it expanded and slid up the taper abit. Expanding the clutch hub ever so slightly in the process. Leading to the movable sheeve sticking and not returning to fully open. No visible defects on clutch shaft and no binding at spider or cover bushing.

I would have to agree with this logic. When the aluminum sheave heats up, the ID doesn't get smaller... it gets bigger. The material is expanding - the circumference is getting larger.

 

[FatDogX]

I actually spoke with the dealer the other day and we got to talking about this and I asked him if they ever figured out what happened. He said they took it apart and the inside clutch sheeve was actually broke / cracked all the way around.

As far as the other one, I'll have to do some more checking as that one went to a different dealer.

 

[polaris88]

Contact Indydan, he has a fix for this problem on the clutches sticking. We had 5 clutches come in this winter all doing this same thing. All of them under 1000 miles on clutches. Got them back and they worked great!!! None came back for any problems.