Once upon a time, I had a belt blower, then Mike Knapp and Clutchmaster did some magic

[KnappAttack]

24x ISR world drag race champion... awesome having a guy like you offering help to all on here. Much appreciated.

Question. I’ve ran TDS big tunes with the dalton BO and always ended up at 3-3. One thing I’ve always ran lighter weights with lighter primary springs. Could this be why when I try more secondary tension I get major belt slippage? Would I need to use a stiffer primary spring and heavier weights to make it work? I always test with my TD gps so I know what works and what doesn’t.

If you get slippage it would be because its slipping in the primary then. Big power needs big weights to grip the belt also. Imagine a drill press with a 1" bit in it trying to punch holes in a 1" steel plate, the belt starts slipping, what do you do? You tighten the belt enough that it doesn't slip anymore right.

Same thing with a snowmobile belt. To tighten it up you have to do a number of things, I should say you can do a number of things. Take away helix angle, add stiffer secondary springs, add primary weight, take away primary spring, all or any combination of these things will "tighten" the grip on the belt. The trick is to get the balance of the upshift and backshift you like.

Typically the primary likes to slip in low ratios and the secondary will slip in the higher ratios, simply because of the dia you are trying to grip the belt at. It's all a balancing act to make it work and work happily. Now throw in different belts, different tunes, different traction and snow conditions. Its a compromise to make it work in the conditions trail rides run in. One day its hardpack, the next day it could be 15" of deep snow!

 

[Fleecer]

Makes sense, neither of those tunes make the big power to NEED a stiffer secondary spring. If it ain't broke, don't fix it.

You only NEED stiffer springs on the big power tunes.

If you have big power and can't keep a hold of the belt on the secondary you HAVE to increase the side pressure for the gripping force needed.

Good point Mike, what weights are you using?

 

[KnappAttack]

Good point Mike, what weights are you using?

Dalton DTYA-1 loaded to 81.6G, 1" in tip and 5/8" in heel sticking out and loctited in. Pulling 9000 bottom to top in 15" deep snow, think I may have to weight it up more for hardpack! Really have it coming around now with the heavier EPI purple set at 0-1 on 35 helix and 8DN belt. May be ordering up some larger straight helix's to play with. Man this sled is fun now! Backshifts properly now and super responsive. Finally keeping belts on it and its a rocketship too boot.

 

[74Nitro]

Dalton DTYA-1 loaded to 81.6G, 1" in tip and 5/8" in heel sticking out and loctited in. Pulling 9000 bottom to top in 15" deep snow, think I may have to weight it up more for hardpack! Really have it coming around now with the heavier EPI purple set at 0-1 on 35 helix and 8DN belt. May be ordering up some larger straight helix's to play with. Man this sled is fun now! Backshifts properly now and super responsive. Finally keeping belts on it and its a rocketship too boot.

290hp setting?

 

[ClutchMaster]

There’s a lot of difference between machines. The only thing I can come up with is some of it is tune related, some of it is differences in alignment.
I’m digressing back to issues ive seen on the Arctic Cats, even a small amount of parallel difference can make one sled burn belts and the other run just fine, same clutching.
I think our sleds are better aligned than the older cats, but still I feel they can’t all be exactly the same.
Small alignment discrepancies can be tuned out, this is some of what is happening here I believe.

Hey Knapp,
Why are Ski-Doo riders like fat chicks?

 

[Fleecer]

Dalton DTYA-1 loaded to 81.6G, 1" in tip and 5/8" in heel sticking out and loctited in. Pulling 9000 bottom to top in 15" deep snow, think I may have to weight it up more for hardpack! Really have it coming around now with the heavier EPI purple set at 0-1 on 35 helix and 8DN belt. May be ordering up some larger straight helix's to play with. Man this sled is fun now! Backshifts properly now and super responsive. Finally keeping belts on it and its a rocketship too boot.

So you're using Dalton weights....that blows my theory.

Which primary spring?
Stock 14.5 rollers or bigger?
Are you back to 21 top gear?
Did you update tune when you went from WAI to air box? If not, does running a little richer cost a few rpm?

 

[fatchance]

What tune with that weight on HH? Primary spring and secondary spring?

I'm running the hurricane 270R and 290R. 45/33 which has had me chasing my tail a bit, but I've got it dialed in pretty good with the Dalton black/ lime and the TP orange up front.

 

[Shagnos]

Running HH thunder weights. And I know I’m way light compared to most. I know they ACT heavy but I’m guessing I’m 10 grams under guys using Daltons. I don’t know right now but I think I’m At around 67 grams on HH. I can post exactly if need be but pretty sure around 67

72 grams HH, Evo stage 4 . What tune are you running?

 

[ClutchMaster]

72 grams HH, Evo stage 4 . What tune are you running?

He’s probably out riding by now, actually I know he’s out riding by now.
TD power trail tune I believe.

 

[KnappAttack]

290hp setting?

Yes.
That clutching may be spot on for the 270 setting when I hit the hardpack though.

There’s a lot of difference between machines. The only thing I can come up with is some of it is tune related, some of it is

Hey Knapp,
Why are Ski-Doo riders like fat chicks?

Don't know, why?

So you're using Dalton weights....that blows my theory.

Which primary spring?
Stock 14.5 rollers or bigger?
Are you back to 21 top gear?
Did you update tune when you went from WAI to air box? If not, does running a little richer cost a few rpm?

Dalton Black/Blue. Engaging at 2900 or so, nice and smooth and no slippage.
Stock 14.5 rollers.
22/41 gear to make up for the longer 8DN belt. Belt lowers OD and gearing about 3-4MPH, one more tooth adds back about 6MPH or so.
No change to tune from stock box to WAI. I did put back the WAI on it as I added a ton of vents to the sled the week in the clutch and frontal area, but with vents completely plugged yesterday in the deep snow and looking like an iceberg, can you imagine the heat the WAI was sucking? Stock box usually does cost a few RPM yes. I wished yesterday in the deep I would have had the stock airbox on it! Oh well, a couple of little field test passes ended up being a 100 mile deep snow ride/thrash test session.

 

[ClutchMaster]

Hey Knapp,
Why are Ski-Doo riders like fat chicks?

Because they are fun to ride with, until your Yamaha friends see you with them!

 

[KnappAttack]

Because they are fun to ride with, until your Yamaha friends see you with them!

But quite fun to poke fun at when you beat them at the pumps too! Hey, I like the Doos a lot, just not the two-strokes. And you never want to ride behind them either! Isn't it funny how after riding four-stroke for so long you just can't stand the two-stroke smell anymore!

 

[SumpBuster]

But quite fun to poke fun at when you beat them at the pumps too! Hey, I like the Doos a lot, just not the two-strokes. And you never want to ride behind them either! Isn't it funny how after riding four-stroke for so long you just can't stand the two-stroke smell anymore!

Except for klotz...that still smells sweet in a nice running sled....but only for a whiff or two.

 

[ClutchMaster]

Except for klotz...that still smells sweet in a nice running sled....but only for a whiff or two.

I put Klotz in the girlfriends essential oils diffuser, she actually likes it too!

 

[STAIN]

Question. Is the primary suppose to close ABout the same rate the secondary opens? I know the cat white seems like the primary is closing/ gripping belt way to fast for how slow the primary is opening. Correct me if I’m wrong here. But don’t you want the two to open/close about the same rate?

That is what you are shooting for. Matching shift rates of both clutches. You dont want one fighting the other====heat