Primary clutch issues?

kanedog

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Hey friends, I have seen over the course of last winter a handful of Primary clutches explode on the 18+ ctech Arctic cats. Has anyone else had this issue? it looks like the outer sheeve is too thin and cracks near the center. Wondering if this is a common thing among everyone or just aggressive riders.
Would you happen to have any pics? Post em up if you do. Cheers
 

kanedog

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#1 notice how the metal is bent out from the cover being pulled against the cover bushing
#2 is the result of the recurring flexing/stress events of the cover clearance issues
#3 although not yet occurring, could be the cracked piece departing the clutch at high speed. F335328D-B939-4073-9C1B-C09291903973.jpeg
 
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Fredrik

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Checked my primary it can get full shift
sheaves touch before inside cover bushing touch spider nut
i have machined down stock spider shim to 1,5mm stock is 3mm
nut and spider thread are level
also cluth springs should be centered on inside diameter so they can grow when compressed.
Checked agiain with a feeler when sheaves touch i have 0.15mm clearence between spider nut and cover bushing.
 

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Octanee

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Mine also has that cracking too, likely from the factory not fitting it on right. though Im not worried about that part of it, I don't see any other cracks so far
 

kanedog

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Checked agiain with a feeler when sheaves touch i have 0.15mm clearence between spider nut and cover bushing.
Why did you machine the spider shim 1.5mm? That works out to .059”.
 

Fredrik

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Why did you machine the spider shim 1.5mm? That works out to .059”.
Yes cut stock shim on lathe
you need a small id chuck
tried with regular shim washers but that will add belt to sheave clearence and also tuck weight more
the stock shim figure is for a reason bigger od than clutch bearing with cutouts so flyweights doesnt catch.
 

Fredrik

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Why did you machine the spider shim 1.5mm? That works out to .059”.
I ride low alt 0-3000 ft need around 73-74g weights it gets sluggish low end when untucked,
tried 70g weight welded up to 73 under tip low like turbo weights nice bottom end sled felt light but lost on mid and high end this was with stock shim.
 

Fredrik

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Checked one 2020 hardcore alpha scandinavian modell and the shim is redused to around 1,5mm so new ones wont have this problem,cat also changed weights helix and secondary spring 2020 with low alt calibration will run good box stock.
 

cbc24

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Would you happen to have any pics? Post em up if you do. Cheers
I dont off hand, I seen one grenade at a hillcross event last winter, it ripped apart the clutch cover, secondary, side panel, belly pan, upper aarm , shock and broke the running board lol. we were also in Revy deep into Joss where the spider blew apart taking a chunk out of the outer sheeve. we tried to limp it out but ended up leaving it in the valley bc it piled the crank up. That is interesting to see all these outer covers fracture. Really curious to see the longevity of these clutches after replaving to a stronger outer cover.
 
Mar 31, 2010
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I’ve had 3 ctec sleds
2018 162” x 1 primary
2018 153” X 2 primary
2020 154” alpha x1 primary
Have done a primary clutch pop on all of them now the 2020 at just 190 miles real pain As It wrecks a lot of stuff, I inspect the clutch every ride as you can usually see a crack start up the outer sheeve where the belt rides, not sure what to do at this point
Also on the 2018s averaging about 400-500 miles to a belt but on the 2020 me and a couple buddies were pulling threads on belts at 170 miles ? Did they change something ?
20B711E6-C87E-4BD8-93AA-4E68B072A66F.jpeg 257944D0-371C-4FD1-B445-B30B598D3055.jpeg 20B711E6-C87E-4BD8-93AA-4E68B072A66F.jpeg 257944D0-371C-4FD1-B445-B30B598D3055.jpeg
 

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boondocker97

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3.5 Pitch drivers give a slightly higher final gear ratio. That coupled with the added traction of the Alpha track/skid might be putting more strain on the belt than what you've seen in the past.
 

sno*jet

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Dang fellas, at this point I might suggest '17 clutches till they get this figured out. They are not bad at all, don't bottom out on the clutch cover, same belt life or better maybe? nice low engagement, belts are cheaper... glad I didn't hop on the roller bearing clutch train in 18
 

Octanee

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Damn! I've been inspecting mine after every ride and so far at 1800 km the clutch has been fine. I'm not in and out of the throttle all The time and generally never peg it down the trail and only on the hills which should keep it from coming close to bottoming out the cover? Knock of wood anyways.
 

yz250_

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I’ve had 3 ctec sleds
2018 162” x 1 primary
2018 153” X 2 primary
2020 154” alpha x1 primary
Have done a primary clutch pop on all of them now the 2020 at just 190 miles real pain As It wrecks a lot of stuff, I inspect the clutch every ride as you can usually see a crack start up the outer sheeve where the belt rides, not sure what to do at this point
Also on the 2018s averaging about 400-500 miles to a belt but on the 2020 me and a couple buddies were pulling threads on belts at 170 miles ? Did they change something ?
View attachment 336617 View attachment 336618 View attachment 336617 View attachment 336618

On a side not, the trees in the backgroung look really cool
 

cbc24

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So a buddy of mine works at our Arctic cat dealership, he mentioned to me that this primary is essentially the same as the ones in polaris rzr sxs. Since Cat contracted the the clutching with team, I am wondering how similar they are? i can see the constant on off behavior with the a snowmobile being hard on them!
 

Qreiff

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On my '18 I had the center bearing fail. Changed on warranty with no issues. Since then, ZRP cover, balanced by Patrick and she is smooth as glass! Stock balancing is no where it needs to be in my opinion. Team should be doing much better. Patrick took a significant amount to balance my clutch. No wonder the stock ones crack and explode. Balancing is key at 8000 RPM+!!
 

bjd68

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On my '18 I had the center bearing fail. Changed on warranty with no issues. Since then, ZRP cover, balanced by Patrick and she is smooth as glass! Stock balancing is no where it needs to be in my opinion. Team should be doing much better. Patrick took a significant amount to balance my clutch. No wonder the stock ones crack and explode. Balancing is key at 8000 RPM+!!
How many kms or miles did u have when the center bearing went?
 
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