2017 Mountain cat Redline Turbo clutching

[Levithan]

Hey Guys.
Got my turbo kit used, it had an 85/255 primary spring with the stock 180/240 secondary spring, 76gram dalton weights and the stock 48 straight helix.
Never used the primary spring as i wanted a higher engagement(think i goofed on the high side 290lbs though).
I changed it to a venom purple/red spring(140-290) this brought the engagement up to around 3600rpm if i remember correctly.
My issue is, i get serious belt slippage(like throw you over the bars) when the boost hits and the clutches are fairly cool when i first start to ride.
After they warm up it seems to go away but it may still be slipping a bit(i don't think so but my buddy has a different opinion).
I just changed back to the 85/255 primary spring to give it a shot and see if maybe the 290lb of the venom is not allowing enough belt squish when the boost hits.
Haven't ridden it yet but i know the primary starts to engage around 2900rpm(seems low to me).
I have done my clutch maint and sanded my sheaves with red scotch bright and cleaned with brake clean to no avail, have also installed a new belt and broke it in correctly, no change.
My question is for anyone running a setup like mine as to what they are running for clutching.
Running around 8200 for rpm in renshaw and vale, not sure exactly of altitude(6k feet maybe?)
Running 6-7psi

 

[Levithan]

Hmm 52 views and not a single response?

 

[E-Zmoke]

Did you notice any change when you changed the spring? Better or worse? Usually belt slip is caused by wet clutches. The proclimbs were notorious for belt slip on engagement because of the snow scoop they decided to put on the panels and the huge gaping hole in the top of the side panel. Does this happen all the time right from the trucks or usually only while your riding? As for turbo clutching you were on the right path with the primary spring change you definitely want the higher rate spring in there. I personally like them to hit even higher around 4200 seems to be the sweet spot. Tough to find a spring that will hit that hard though Dalton makes a few good ones. I would put the higher rate spring back in since you already have it in and simply remove the snow scoop and cover up your panel holes. Leave the 48straight in load the weights all the way to the tips if you haven’t already? Is track tension correct? Just make sure your track isn’t too tight as well could be something small like a overtightened track could be the culprit as well but in going to guess you just simply have a classic case of a wet proclimb clutch


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[E-Zmoke]

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[Levithan]

Haven't ridden it yet with the lighter spring, will be this weekend.
I have cut the snow scoop back and put on frog skinz, helped a little in deep snow but not as much as i hoped.
So if i ride some trail and stay out of the snow, the clutches work fine.
However if i'm in the snow and let it sit for half hr or so(lunch etc) i need to do some light pulls(out of boost) to let the clutches/belt warm before i get on it, then it seems to work again.
What do you run for weights?

 

[E-Zmoke]

Haven't ridden it yet with the lighter spring, will be this weekend.
I have cut the snow scoop back and put on frog skinz, helped a little in deep snow but not as much as i hoped.
So if i ride some trail and stay out of the snow, the clutches work fine.
However if i'm in the snow and let it sit for half hr or so(lunch etc) i need to do some light pulls(out of boost) to let the clutches/belt warm before i get on it, then it seems to work again.
What do you run for weights?

I run Dalton weights, they are a great weight. The only clutching change you need to make is to put your heavier spring back in.

Your answer of if your on the trail the belt slippage doesn’t occur this is the key to the problem and key to the solution. This 100% confirms you are getting wet clutches and you need to address this before your next ride. Whatever you have done to your panels it is not working. Now to be very clear what I call the snow scoop is the wire mesh type pet screen material that directly sends snow straight onto the clutches. I have personally sent over 200 of these snow scoops back to Arctic cat. They finally changed this in 2018 so it’s no longer an issue but for 3 straight years we got them right from factory. Your 17’ is one of those years. You can chalk this one up with one of the worst designs in the history of snowmobiling.

Please see the attached pic of your 17’ panels the snow scoop is #1 and the #2 doesn’t really help the situation at all but isn’t the culprit of your belt slippage, both need to be changed to a proper vent material. I still have a few of my custom kits available if you need a kit. But anything instead of that pet screen material will be better then going for a ride with it still intact. Remove it and put duct tape over the hole will give you better results then riding with it intact again.

You said you put frog skin over it can you please post a pic of your clutch side panel?

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[Levithan]

Thanks man, i put a frogskin on the exhaust side where the big hole is. All i have done to the clutch side is cut the lower scoop back a few inches and stuffed a sponge up in there to prevent snow from coming in.
Upon your advice from last time, i have removed the lower scoop entirely and taped it off for now.
The upper scoop is still there as it holds the vent in but i have now also taped that off as well.
Do you not think the lower engagement spring will provide more belt grab as it is an 85/255, vs the 140/290?
Also what about the large v shaped opening towards the rear of the panel and the small grated one near the bottom of the panel?
Do these cause issues as well?
Does the clutch not need some of this for cooling?

 

[E-Zmoke]

Thanks man, i put a frogskin on the exhaust side where the big hole is. All i have done to the clutch side is cut the lower scoop back a few inches and stuffed a sponge up in there to prevent snow from coming in.
Upon your advice from last time, i have removed the lower scoop entirely and taped it off for now.
The upper scoop is still there as it holds the vent in but i have now also taped that off as well.
Do you not think the lower engagement spring will provide more belt grab as it is an 85/255, vs the 140/290?
Also what about the large v shaped opening towards the rear of the panel and the small grated one near the bottom of the panel?
Do these cause issues as well?
Does the clutch not need some of this for cooling?

Put the 140/290 back in or go even stiffer, don’t worry about the large v shaped opening near the knee console or the small one at the bottom is fine as well leave them both open for air flow, ideally you want proper vents over the snow scoops but taping for now will get you through a weekend yes this will cause more heat but it’s better then a wet clutch and belt slippage. Good luck and report back


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[Levithan]

Road the sled in renshaw on the weekend, was deep.
Taped off the vents and removed the lower snow scoop.
No belt slippage at all but was running the 85/255 to see how i liked it.
The engagement is to low at 2900rpm but the 255 up top seem to be more of a linear pull when the boost hit other than the sudden onset of the 290.
Thinking i want more engagement on the bottom, somewhere around 3600-3800rpm and maybe a slight amount more on the top maybe like a 265-275.
Found the black epi ps4 spring rates at 145/280 on a polaris 2.50"-1.25", from what i can tell from cross reference charts, should be 135/270 on a cat at 2 9/16-1 5/16

 

[E-Zmoke]

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