AC Primary/Secondary setups-WTH

[Arctic Thunder]

Cat clutching Ideas.
Sled: 2009 M1000 Twisted Race Gas Turbo, 10psi boost, 162 Power claw track, Stock M1000 gearing, 40-47 Progressive helix

Observation: Couple wide open runs on the trail and the belt is ruined. Missing about 4-5” of the inside teeth. Rest of the belt looks new. Black marks on the outside diameter of the primary clutch. No scuffs on the helix from the belt bottoming out in the secondary, no black marks from the belt slipping in the secondary.

Measurements: Secondary
Using a 0648-774 Cat secondary spring.
Free length is 5.538"
Compressed is 1.461"
Secondary clutch spring clearance is 1.521" this is with a shift assist and both of the .153" thick shims installed.

Notice how the secondary (without a spring) full open travel is WAY past where it should ever operate. The belt can actually fit down far enough into the secondary to hit the helix. The red marks are the straight cut on the secondary and the gap between the bottom of the secondary and the belt. The blue line is the farthest down into the secondary the belt should ever get. (See Secondary Pic)

So what is happening here?
My thoughts, without a mechanical stop in the secondary the belt can climb right out of the primary. We don’t want to shim the secondary spring to be the stop because we will be breaking springs. So what about not cutting the top of the helix back so it can’t travel as far. The rollers will top out in the now shorter helix. It appears the current stop is the top of the helix. (See Helix Pic)


I don’t think we need to let the belt ANY farther down into the secondary than what it would take to get the belt to the top of the primary. With 250+HP it is pretty easy to climb out of the primary. My guess is this is around 80-85mph. So even in a climb a turbo sled can hit these tracks speeds. So we need to hold the secondary back to keep good squeeze and contact with the primary.

So I don’t know the magic number to add to the secondary helix but I would say it is going to be .125” or so plus or minus.

Last question: why would Arctic Cat allow the secondary to open this far? Why would they let the belt climb out of the primary?

I would think when the belt hits the top of the primary it is in full shift. At the point this happens the secondary needs to hold back.

Last thought. I am sure AC figured if you have a bone stock M1000 with stock everything you will run out of HP to pull the belt to the top of the primary. But as people add pipes, intakes, heads, turbo's ect. We are just over powering the gearing and the setup. Remember back in the day when AC had all the belt problems on the ZR's. They were geared for about 90MPH. And guys were getting it, easily, and of course blowing belts. AC's fix, gear it up to 119MPH so it cant get to full shift out. Problem solved. I think we are in a simailar situation here, but we don't want to make big gearing changes due to mountain riding styles and other belt issues.

Thunder

 

[clutch]

Do you have the white plastic sleeve on the shaft of your secondary? Cat puts that in to be a stop. If so has it been shortened to allow it to shift to far?

 

[fordpickupman]

A stop is an interesting idea, but would it hit too hard and cause other problems? What about a short finish angle that would load aggressively to keep it out of that area. Of course a turbo would probably still blow right passed it anyhow.

Better put an 11" secondary on it.


FORDpickupman

 

[Arctic Thunder]

Do you have the white plastic sleeve on the shaft of your secondary? Cat puts that in to be a stop. If so has it been shortened to allow it to shift to far?

Hmmmm, I see how this would work. Mine has never been touched. so it is stock length. In the pictures that is.

 

[Arctic Thunder]

A stop is an interesting idea, but would it hit too hard and cause other problems? What about a short finish angle that would load aggressively to keep it out of that area. Of course a turbo would probably still blow right passed it anyhow.

Better put an 11" secondary on it.


FORDpickupman

Don't know. But I know for a fact if the belt jumps out of the primary all hell breaks loose. So somehow I have to keep it from getting that far. I am sure it would put one heck of a load on the motor mounts and such but that's the idea. I don't want the belt climbing out of the primary.

What would the 11" secondary do?

So clutch do you think the secondary should shift all the way out like it does? I bet all the stockers do. Wish I would have measured the spacer and noticed how much room I had.

Thunder

Thunder

 

[fordpickupman]

I guess my thought was that the bigger secondary would have more travel. But that doesn't really address your concern of the primary spitting the belt out.
Maybe the primary is the one that needs a stop. Or do you want the secondary to control that? I'm no guru, still learning.


FORDpickupman

 

[clutch]

If I remember correctly, the shift assist is slightly larger I.D. and the plastic spacer can actually go inside of it effectively makin it shorter and allowing it to overshift. Something to look at anyway.

 

[Desperado]

SA

My shift assist was a slightly smaller ID than the white plastic piece. It set on the top plate of the SA. Interesting that some SA may be a larger ID causing the white spacer to drop in the hole...