Primary clutch issues?

kanedog

Undefeated mountain clutching champ of the world.
Lifetime Membership
Oct 14, 2008
1,798
1,443
113
55
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

Undefeated mountain clutching champ of the world.
Lifetime Membership
Oct 14, 2008
1,798
1,443
113
55
#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
 
Last edited:

Fredrik

Member
Nov 29, 2007
89
8
8
38
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.
 

Attachments

Octanee

Well-known member
Lifetime Membership
Nov 15, 2010
900
85
28
39
Cranbrook Bc
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

Undefeated mountain clutching champ of the world.
Lifetime Membership
Oct 14, 2008
1,798
1,443
113
55
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

Member
Nov 29, 2007
89
8
8
38
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

Member
Nov 29, 2007
89
8
8
38
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

Member
Nov 29, 2007
89
8
8
38
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.
 
Premium Features