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Clutch Help

P

ProX00

Member
Messages
44
Age
56
Location
UP
Country
USA
Years Snowmobiling
5
Snowmobile
Switchback ProX
I recently jumped ship from Yamaha and bought a Switchback ProX with a studded 1.352 Cobra with 37/22 gearing. So far I couldn't be happier. I ran the sled stock for the last month. I would line up against my other buddy's on their Yamaha Apex's and I would get a sled length lead then we would pretty much be dead even to 100 start to finish. Last week I bought a clutch kit off a friend who sold his Assault. It is a Northstar Performance kit. He loved the kit and told me I would to. the kit included 10-68 weights, 120/310 primary, 140/220 secondary, and a mystery helix from Venom. I installed the kit and tested it against the group thinking I would certainly at least get a few lengths better on them but it was basically the same. I lost about 300rpms(stock was getting 8100 and new setup was at 7800) out of the hole but would climb to 8300. Backshifting was great. The kit did not have any gearing for the ProX. If I were to run 1.74 gearing would that help bring the rpm's back and get this clutch kit on track? How would 38/21,1.81, gearing work with this setup? For the record, I am 210 without gear.
 
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Do you currently have the stock cobra 1.68 gearing or the 1.75 BC X 1.86 gearing?
 
Your rpms seems good at the end. But the 7800 start seems low. What temp outside? Does your belt deflection make the track creep on the stand? It should.
 
Putting in the 1.74 ratio would help.
Ru4real made a great point.

Things get overlooked.

Clutch alignment
Belt deflection
Belt to sheave
Clutches &belt cleaned
Track free hang 5/8"
Chain tension

If the helix is a mystery, ditch it. We used to do that in the 90's for guys. Not worth it as its not needed to hide anything from people.
Put a 48/42 full progressive in.

Try this with what you have , 48/42 fp and 1.74 ratio change only. I think it will work
 
Belt deflection, clutch alignment, tack tension, chain tension all good. The temps outside were mid 20's but it was the same temp I ran with the stock kit. Stock I pulled 8000+ out of the hole then rose to 8300+. I'll buy the 48/42 like you recommend and change the gearing to 1.74. What are the thoughts on running 1.81? 38/21 gears.
 
Sounds like my old pro r situation.

Go back to stock, since that was quicker/faster.

Change one thing at a time and test.

At this point, you're looking at changing the sled to suit the kit you bought, when the stock setup works better.
 
There are two angles on his helix. Find out which one has the shallower start, it's very close to a 48-44 I'm sure that will help ur lower rpm off the line. Put the shallower angle in and try it. That's a great spring but not needed if your not running a pipe. Try ur stock spring if it's good
 
Don't buy kits, it's that simple.
On flat land all these companies are doing what me and doc have been saying since the axys came out .It's anywhere from a 48 degree start. +/- 1 or 2. And a 44 degree finish ,+/- 1or 2 of a full progressive. 0-3000' asl.

Here's were I'm at with secondary springs(same as doc)

If your running no studs, stock pipe. Use the stock 123/203. Needs to be light. Heavier like a 140/240 will give you great back shift, but suck on drag race up shift (to much spring). A 120/220 is splitting hairs

If your running studs and they actually get good 60' times and a pipe. You need a stiffer secondary start spring. This is so the belt doesn't get sucked down on a good hole shot . So, a 140,155 start is needed. The finish can be 200-240.

The key is using the lightest springs possible(especially on tss-04) and getting your rpm .
 
Ditto^^^^^^ . IMO on a tied 64-60 maybe +1/2 on either end, and a 123/202, 140/200, or a 140/220. Thinking of trying the SLP magnum wts d/t ease of adjustability for temps above or below freezing. Defiantly can pull more wt when colder, just as Polaris states lighter wts above freezing. On '17's find it interesting when it hits 8500 rpm's for a few seconds it will drop to 8300 and hold. Thinking ECU corrects for the high rpm, 8500 was running 66's in low 20 temps, next day was low 40's and pulling 8300. Thus, the idea of trying easy to adjust adjustable wts
 
Brock said:
Don't buy kits, it's that simple.
On flat land all these companies are doing what me and doc have been saying since 2015. It's anywhere from a 48 degree start. +/- 1 or 2. And a 44 degree finish ,+/- 1or 2 of a full progressive. 0-3000' asl.

Here's were I'm at with secondary springs(same as doc)

If your running no studs, stock pipe. Use the stock 123/203. Needs to be light. Heavier like a 140/240 will give you great back shift, but suck on drag race up shift (to much spring). A 120/220 is splitting hairs

If your running studs and they actually get good 60' times and a pipe. You need a stiffer secondary start spring. This is so the belt doesn't get sucked down on a good hole shot . So, a 140,155 start is needed. The finish can be 200-240.

The key is using the lightest springs possible(especially on tss-04) and getting your rpm .
Click to expand...
If I run 38/22 gearing(1.73) with the 68 chain is it going to be any different than 40/23 (1.74) with a 70 chain? I am running studs but no pipe. Do you think the 140/220 is too stiff? What pipe do you recommend? Can I use the stock muffler? I'll pick one up over the summer since this season looks to be over for me. will adding a pipe require me to change weights or springs? Next winter I expect to have the following setup:

10-68 weights
120/310 primary
140/220 secondary
48/42 fp
BMP or SLP pipe( or other recommended)
1.74
 
TAR pipe,best trail pipe I have tested in the field. Use adjustable weights,CPC,Daltons which ever you prefer this way you can adjust ur rpm as needed
 
Dr.Notadoo said:
TAR pipe,best trail pipe I have tested in the field. Use adjustable weights,CPC,Daltons which ever you prefer this way you can adjust ur rpm as needed
Click to expand...


Do you suggest running the Terra Alps pipe with extra timing via PCV or timing key like the Jaws pipe?
 
Never heard of TAR....is there a web site?
 
Dr.Notadoo said:
If your on a budget get the keyway,its 25 bucks ..the better way would be the PCV..
Click to expand...
Did some research just picking your brain, on the older 800 twins they say the timing key gives better mid but loses top end speed, anyone have much field testing?? Hard to test when you hardly get any snow!!
 
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