Blown Belt

[journeyman]

In pic you can see darker line where belt was riding towards top of primary. Mine too looked like this.....more miles I put darker the line became pronounced. Eventually black snot will start to appear. I think darker line is belt slip at higher speeds. Question I have is why the slip???? Is it binding, low tension, etc???

That's what the million dollar question seems to be. If you go back and read my post on the primary sheaves the person that mentioned it also said something about the cut angles being off and that it could be causing poor belt grip at the top of the sheaves. This is all someone's speculation though. I hope somebody figures this issue out. I want to hear good things about this new sled, not all this. Maybe they need to hire the engineers who developed the previous YXR primary and secondary clutch system. Since that setup came out in 1995 Yamaha's clutches IMHO surpassed everyone else's for performance and reliability.

 

[jonlafon1]

Here's the belt

That top is peeled back quit a bit.. I would not consider that a "clean break" ??. Mine looked nothing like that. Mine was broke in half, like someone cut it with a knife. Not sure if it matters that much either way.. Thanks for the info and pic Soupy

 

[1100saber]

Was just out for a little ride. Approx 6-8" of powder. Did a few pulls on the lake and stopped and checked clutch temps. Belt, primary, and secondary hotter than I would like...and hotter than when I had previously checked them. Drove back to garage and pulled secondary. Pics below show paint/wear marks on the spring in 3 different places. My sled has the torlon rollers and all 3 seem to rest on the helix in correct position. Hoping to have the pocket of my secondary machined before this weekend and re test.

 

[KnappAttack]

If the paint is not worn on every coil, IT IS NOT COIL BINDING!

When coil bind happens, its evident in all coils having paint worn off on both sides of the coil, and its on every single coil.

A little bit of paint worn off is quite normal, especially right under the tangs. You guys gotta quit worrying about things that are not there or not happening.

The factory engineers are not totally stupid!!

 

[1100saber]

If the paint is not worn on every coil, IT IS NOT COIL BINDING!

When coil bind happens, its evident in all coils having paint worn off on both sides of the coil, and its on every single coil.

A little bit of paint worn off is quite normal, especially right under the tangs. You guys gotta quit worrying about things that are not there or not happening.

The factory engineers are not totally stupid!!

Well I guess that's good news then. This is a whole new clutch setup for me and I'm learning just like everyone else. I for sure don't have evidence of paint worn off on all/both sides of coil. BUT I do think it's slipping the belt. My previous turbo sled had the clutches pictured below. They were "set and forget" and had zero belt issues.

 

[shagman]

If the paint is not worn on every coil, IT IS NOT COIL BINDING!

When coil bind happens, its evident in all coils having paint worn off on both sides of the coil, and its on every single coil.

A little bit of paint worn off is quite normal, especially right under the tangs. You guys gotta quit worrying about things that are not there or not happening.

The factory engineers are not totally stupid!!

Get your tools out and measure the pocket of one of these secondary's them measure the collapsed spring with the twist applied. Then try to say that again. If you haven't done the work don't comment. FYI I do have an engineering degree and 20 + years in a fab shop. This secondary coil binds just like the old one.


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[KnappAttack]

Get your tools out and measure the pocket of one of these secondary's them measure the collapsed spring with the twist applied. Then try to say that again. If you haven't done the work don't comment. FYI I do have an engineering degree and 20 + years in a fab shop. This secondary coil binds just like the old one.


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When springs go into coil bind it shows on the spring, plain and simple. Don't need to measure it if the spring isn't showing it. When the driven quits shifting because of coil bind when running, you WILL see it on the spring. This isn't my first year off the boat either. Ive seen coil bound springs and this pic isn't one that's coil binding.

If the driven quits shifting because of coil bind or running out of travel, the drive is going to keep pulling the belt and it will flat out snap in half like you cut it with a knife. And it will only do it at WFO while tapped out in MPH when it binds, because the drive clutch keeps trying to pull the belt.

Torsion and even compression springs will wear paint off a few coils, it is perfectly normal especially right under the tangs on a torsion driven spring.

Now when ever coil has paint worn off every coil, you will have coil bound it.

Perhaps the driven is showing that it could coil bind when going thru the full driven shift travel, that does not mean that it will given the width and length of belt being run. Generally the front clutch runs out of travel prior to coil binding or running out of travel in the driven. I say generally because using factory centers, belt lengths and widths you will never see the driven run out of travel or bind before the drive clutch.

 

[Snowaddict]

"If the driven quits shifting because of coil bind or running out of travel, the drive is going to keep pulling the belt and it will flat out snap in half like you cut it with a knife. And it will only do it at WFO while tapped out in MPH when it binds, because the drive clutch keeps trying to pull the belt."
Pretty sure that's exactly what happened in a few of these cases, the belt snapped right in half.

 

[shagman]

When springs go into coil bind it shows on the spring, plain and simple. Don't need to measure it if the spring isn't showing it. When the driven quits shifting because of coil bind when running, you WILL see it on the spring. This isn't my first year off the boat either. Ive seen coil bound springs and this pic isn't one that's coil binding.

1. paint will not fall off right away, put more miles on and it will be gone between all the coils.

If the driven quits shifting because of coil bind or running out of travel, the drive is going to keep pulling the belt and it will flat out snap in half like you cut it with a knife. And it will only do it at WFO while tapped out in MPH when it binds, because the drive clutch keeps trying to pull the belt.

2. Correct several people have already had this happen.

Torsion and even compression springs will wear paint off a few coils, it is perfectly normal especially right under the tangs on a torsion driven spring.

3.Correct

Now when ever coil has paint worn off every coil, you will have coil bound it.

4.Correct

Perhaps the driven is showing that it could coil bind when going thru the full driven shift travel, that does not mean that it will given the width and length of belt being run. Generally the front clutch runs out of travel prior to coil binding or running out of travel in the driven. I say generally because using factory centers, belt lengths and widths you will never see the driven run out of travel or bind before the drive clutch.

5.In the case of these clutches with the 8JP belt, the driven clutch will coil bind before the drive clutch reaches full travel. At times with the soft nature of the 8JP the clutches will also get a black ring around the drive clutch near full travel caused by the coil bind in the driven. In this case the clutches heat up and usually the belt will explode in a 100 pieces. Same cause different result.

Like you said not my first rodeo either. But I actually have a Sidewinder to work on these problems and the solutions will be soon.

 

[DC5]

I have to agree with Mike on this. When twisted to 3-3 I have not seen coil bind. The secondary is able to fully compress with the spring installed at 3-3 but not at 6-1. I have tested top speed and it is always able to max out the gearing to expected top speed with no issues. Have 1500 km on my belt and it still looks great. Install good primary clutching, an 8dn belt and good rollers and there is no issues. Just my opinion.

 

[jonlafon1]

I have to agree with Mike on this. When twisted to 3-3 I have not seen coil bind. The secondary is able to fully compress with the spring installed at 3-3 but not at 6-1. I have tested top speed and it is always able to max out the gearing to expected top speed with no issues. Have 1500 km on my belt and it still looks great. Install good primary clutching, an 8dn belt and good rollers and there is no issues. Just my opinion.

Are you running stock boost levels? How many studs if any? Thanks

 

[cannondale27]

Before you guys start making the 8DN the norm be sure to tell those who haven't had them on a nytro or Viper which runs at 9000+ clutch rpm how quickly the 8DN wears into Primary sheave faces. It is far from a perfect belt.

 

[Moodeyblue]

the 8dn , being a little longer, will not go down as far in the secondary? Is it safe to say an 8jp will contribute to coil bind more so than a 8DN? I guess it depends how far the 8dn goes up farther in the primary if it is even possible to coil bind.

 

[DC5]

I tested the 8jp and 8dn. The 8dn loses 3mph up top due to being longer so gear up accordingly or keep an 8jp on hand for radar runs. I am running TD powertrail with 144 studs.

 

[dsimonRX1]

I ran at 6/1 all last weekend with great results for 300 miles and no blown belts. Changed to Ulmer rollers before I left. I am planning on trying 3/3 as well.