Blown Belt

[jonlafon1]

ive now heard of a few sleds with the daltons and blown belts... could be because they all have tunes...and flat spots seem to keep the clutch from shifting out so a flat spot could be the major culprit..

And has anyone heard of a 17' blowing a 8dn yet?

Did it at 46 miles. 8dn

 

[Fleecer]

For all of you guys blowing belts, what was your break in procedure? How many miles did you put on before you went wide open throttle?

I broke engine in by the book and had over 300 miles before any prolonged wot.

 

[Fleecer]

ive now heard of a few sleds with the daltons and blown belts... could be because they all have tunes...and flat spots seem to keep the clutch from shifting out so a flat spot could be the major culprit..

And has anyone heard of a 17' blowing a 8dn yet?

My buddy blew belt 334 miles, stock everything and all rollers are good with no flatspots. I think issue is in rear clutch, but just my opinion.

Will an apex secondary fit on a winder?

 

[T-Mod]

112 on GPS. I must not be getting a full shift out. Here's what the secondary looked like before I cleaned it. Primary marks are a good 1/4"+ from the top.View attachment 124732View attachment 124731 View attachment 124730

You see the black mark deep in the secondary...most clear in the 2nd photo? The primary is trying to pull the belt deeper in the secondary and its clearly heating and tensioning the belt at that point in the shift and stalling there. That puts a ton of load on the belt. With the power you're making...the belt has no chance. It doesn't look like full shift to me but if I could hold it in my hand an look at it, I could tell a lot more. Take the secondary in your hand and bolt it together without the spring in. Now open it up and lay the belt down inside and see where it sits, relative to the center hub. If the belt nearly touches the center hub, its good. If it stops short and there's quite a gap there, shim-up the helix by putting washers under the helix before you put the nuts on to hold the helix to the towers. Shim it until the belt nearly touches the hub at full shift and you're done. If its already sitting on the center hub, that's your problem. The belt is getting too far into the secondary and its slipping on the sheaves leaving the black mark. If its good right now, your side load nearing full shift is too high...you're squeezing the belt too much on top end. Remember...you need less squeeze at full shift in the secondary than you need out of the hole and through the low middle. Squeeze should drop enough, not to slip...with the least amount of squeeze possible. Do you understand the Trig for calculating torque feedback, based on the helix angles you're running? Too much angle, along with tall gearing will eat the belt on the shift and get it ahead of the primary for the ground speed of the sled. That puts load and heat on/in the belt...not good. It also requires more time to back shift and if it gets behind the primary returning to the top of the secondary, then you hit the throttle hard and you've got bite, you're going to snap that belt in half quicker than #*$&@. There's so much more to all of this...but suffice it to say, "the pattern I see on your secondary is not happy". Make sure your belt has plenty of DEFLECTION in neutral...if it doesn't and the sled creeps or pulls on the motor in neutral, with the power these things make, your belt will break in short order!

 

[actionjack]

Wow great info

I know a blown belt is inevitable since I still have an 07 Attak. What concerns me is I have seen a few photos of blown out plastic from the belts grenading on the SW. I have never before witnessed a blown belt on a sled resulting in replacing body work. Since there are embarrassingly no parts supply to speak of I guess those riders are frankensled patching these holes and that sucks to me. Even if the part was available sure makes a blown belt more expensive. I'd really like to wrap up a spare belt and keep it under the clutches under some kind of plate to protect the pan and the next victim. I know Belanger sells a piece that seems expensive. Can I use it and place a wrapped spare belt under it? Does anyone know of any solutions for this?

 

[Beerman]

You are clearly burning the belt in the secondary. Do you have any oil contamination?

No wonder your top speed is not good...

The 8dn belt should help with the slipping.

I thought I had cleaned up all the oil from the dealer prep of the air filter, it's possible I didn't. I took it apart at my in-law's cabin and the best he had to clean it with was turpentine, I'll take it all apart again today now that I'm home and use brake cleaner. I have OSP's belt adjuster so I can adjust for the 8DN pretty easily, which I'll get from the dealer tomorrow. I did have the deflection pretty tight to get the belt as close to the top of the secondary as possible without any creep.

 

[Beerman]

You see the black mark deep in the secondary...most clear in the 2nd photo? The primary is trying to pull the belt deeper in the secondary and its clearly heating and tensioning the belt at that point in the shift and stalling there. That puts a ton of load on the belt. With the power you're making...the belt has no chance. It doesn't look like full shift to me but if I could hold it in my hand an look at it, I could tell a lot more. Take the secondary in your hand and bolt it together without the spring in. Now open it up and lay the belt down inside and see where it sits, relative to the center hub. If the belt nearly touches the center hub, its good. If it stops short and there's quite a gap there, shim-up the helix by putting washers under the helix before you put the nuts on to hold the helix to the towers. Shim it until the belt nearly touches the hub at full shift and you're done. If its already sitting on the center hub, that's your problem. The belt is getting too far into the secondary and its slipping on the sheaves leaving the black mark. If its good right now, your side load nearing full shift is too high...you're squeezing the belt too much on top end. Remember...you need less squeeze at full shift in the secondary than you need out of the hole and through the low middle. Squeeze should drop enough, not to slip...with the least amount of squeeze possible. Do you understand the Trig for calculating torque feedback, based on the helix angles you're running? Too much angle, along with tall gearing will eat the belt on the shift and get it ahead of the primary for the ground speed of the sled. That puts load and heat on/in the belt...not good. It also requires more time to back shift and if it gets behind the primary returning to the top of the secondary, then you hit the throttle hard and you've got bite, you're going to snap that belt in half quicker than #*$&@. There's so much more to all of this...but suffice it to say, "the pattern I see on your secondary is not happy". Make sure your belt has plenty of DEFLECTION in neutral...if it doesn't and the sled creeps or pulls on the motor in neutral, with the power these things make, your belt will break in short order!

Great info, some of it is over my head but I'll see what all I can find. Thanks!

 

[Beerman]

Yikes! The primary was worse than I noticed from the belt slipping. Here's the before and after with brake cleaner and the help of a little Scotchbrite pad. I sure hope it was as simple as oil contamination. I'll report back once I have a few miles on the 8DN and a new top speed.

 

[stone88]

If speedo says 126 to 128 and gps 121 it id simply because you are spinning, not because of clutch binding.

Just a little update seeing as we don't have any safe ice I was testing on a plowed road and I put on my button clutch from my Viper and here is my result.

 

[Moodeyblue]

is your sled modded? which helix in the viper clutch? impressive speed anyway.

 

[Turbo Dynamics]

Yikes! The primary was worse than I noticed from the belt slipping. Here's the before and after with brake cleaner and the help of a little Scotchbrite pad. I sure hope it was as simple as oil contamination. I'll report back once I have a few miles on the 8DN and a new top speed.

Turpentine is " greasy" it may have made the situation worse.
Best to use acetone or brake cleaner.

 

[Turbo Dynamics]

View attachment 124824
Just a little update seeing as we don't have any safe ice I was testing on a plowed road and I put on my button clutch from my Viper and here is my result.

Cool stuff!

We are trying a few new helix from Dalton with a member of this forum. We'll see if we get an improvement.

A tcat with Powertrail just went 135mph gps on a plowed road

 

[silverram323]

Let us know on the helix, I would like to get rid of this junk cast stock helix, only 2 of my 3 rollers touch, i Also order 3 cat rollers before i have issues with mine.

What degree is the stock helix?


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[1100saber]

Let us know on the helix, I would like to get rid of this junk cast stock helix, only 2 of my 3 rollers touch, i Also order 3 cat rollers before i have issues with mine.

What degree is the stock helix?


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Straight 35 I believe

 

[DranttelSS]

Straight 35 I believe

Yep