12 Vector Ltx belt issue

[RobX-1]

check on the bottom of the belt gaurd. for some reason the one on my 11 bent down and i was getting rub marks on it.

Well, checked the the underside of the belt guard and although there are belt markings, I believe that is just from the belt starting to delaminate and the pieces hitting it before breaking off. Nothing else shows signs of it coming into contact with the belt that would lead to the top of the belt delaminating:

Put a straight edge on the primary sheaves to see how much wear there is about half way up. Don't worry about the grooving near the bottom, it has almost no effect.
The sheave surfaces need to be straight.
I had this same problem on a rs venture years ago and it was excessive wear half way up the sheaves, eating belts like crazy.

I tried my best to lay the flat edge against the front and back sheaves of the primary but there are some gaps, @74Nitro, is this what you were referring to or is this not excessive enough for it to cause my belt delamination issue:

 

[RobX-1]

Here's with the belt guard installed; nothing appears to be making contact with belt:

 

[74Nitro]

Here's with the belt guard installed; nothing appears to be making contact with belt:

View attachment 180586

Yes, so what happens is as the belt travels up the sheave there will be a point where only the top portion of the belt is being pinched, and of course the top comes off then.

 

[RobX-1]

Yes, so what happens is as the belt travels up the sheave there will be a point where only the top portion of the belt is being pinched, and of course the top comes off then.

Strange that this is finally rearing its ugly head after all these years. I’ve run the 8DN since 2003 in all my Yamahas with great longevity.

X2 on this becoming an issue now all of sudden as I have a close to 24k on my 08 primary and it does not have this belt delamination issue and it too uses the 8DN belt. I know there were changes to the primary in relation to the set screws for the roller pins but did they also change material on their primaries where now the harder make-up of the 8DN is rearing its head?

 

[sxr70001]

I wonder if at some point the springs start to lose tension on these older sleds and don't grip the belt as well causing excessive heat. I replaced belts on 2 of my riding buddies sleds this year when out riding, an 06 Venture and an 08 Vector. The belts were fairly new. I have taken to carrying an 8dn on my sidewinder just for this reason. Maybe this summer i will go through their clutches and replace springs and anything else that looks worn. Interested to see what you guys figure out.

 

[maim]

mine bent enough on the 11 that the drag n fly weights where hitting on the belt gaurd. it is on clutch #3 in 24000 mi as both other ones started cracking at the bottom. i usually pop the outer layer off on mine around the 2000 mi point when i get froggy with it.

 

[Apexpat]

My 13 Apex has 18,000 miles original clutch, used only 8DN belts no belt issues. 12 Vector with 11,000 miles less horsepower eating belts, makes no sense.

 

[74Nitro]

X2 on this becoming an issue now all of sudden as I have a close to 24k on my 08 primary and it does not have this belt delamination issue and it too uses the 8DN belt. I know there were changes to the primary in relation to the set screws for the roller pins but did they also change material on their primaries where now the harder make-up of the 8DN is rearing its head?

It's not a new issue. It was over 12 years ago when I came across this. It was an RS venture, started to eat belts, the top always came off first.
The owner was even on a trip in Michigan and came across a group of guys that worked for Yamaha and they had nothing to offer as to his problem. I went through everything related to clutching on that thing. Everything was in good order. Then somehow I got the idea to check the primary sheaves for wear.
Once the sheaves were changed.....problem solved!

 

[Apexpat]

It's not a new issue. It was over 12 years ago when I came across this. It was an RS venture, started to eat belts, the top always came off first.
The owner was even on a trip in Michigan and came across a group of guys that worked for Yamaha and they had nothing to offer as to his problem. I went through everything related to clutching on that thing. Everything was in good order. Then somehow I got the idea to check the primary sheaves for wear.
Once the sheaves were changed.....problem solved!

So your solution was a new primary. Did you have the grooves machined smooth or just replace with a new clutch? What doesn’t make sense is why this isn’t a problem for most Yamaha sleds. I’ve owned 5 other 4 stoke Yamahas using the 8DN belt with zero issues. You’d think this would be widespread rather than a few of us having this issue with the 3 cylinder sleds.

 

[74Nitro]

So your solution was a new primary. Did you have the grooves machined smooth or just replace with a new clutch? What doesn’t make sense is why this isn’t a problem for most Yamaha sleds. I’ve owned 5 other 4 stoke Yamahas using the 8DN belt with zero issues. You’d think this would be widespread rather than a few of us having this issue with the 3 cylinder sleds.

Why is the sky blue?
Why don't they sell Coke and Pepsi at the same restaurant?
How do brown chickens give brown eggs but brown cows don't give brown milk?

Why the deep dive on why this happened?

We found the problem, who cares why it doesn't happen exactly the same on every sled.

Get some straight used sheaves or new ones and get riding.

 

[CaptCaper]

Strange that this is finally rearing its ugly head after all these years. I’ve run the 8DN since 2003 in all my Yamahas with great longevity.

Same here... 40k miles combined on my machines in 20 yrs never a belt failure. With oem belts.

 

[74Nitro]

With all due respect guys, you're over thinking it.

Change, or repair the worn parts and carry on.

 

[Apexpat]

With all due respect guys, you're over thinking it.

Change, or repair the worn parts and carry on.

I don’t think I’m over thinking was just trying to figure out why the issue when I have 20 years on these machines with the same clutch’s and zero issues. I’m fine that stuff breaks but I don’t want to replace with a new clutch and have this happen again. Just confirming that people think 8DN belts are the issue for the worn primary’s. I appreciate yours and everyone else’s help on the issue. That’s why this continues to be one of the best forums for Yamaha owners.

 

[Stubbs]

I don’t think I’m over thinking was just trying to figure out why the issue when I have 20 years on these machines with the same clutch’s and zero issues. I’m fine that stuff breaks but I don’t want to replace with a new clutch and have this happen again. Just confirming that people think 8DN belts are the issue for the worn primary’s. I appreciate yours and everyone else’s help on the issue. That’s why this continues to be one of the best forums for Yamaha owners.

Simple, the three bangers aren’t clutched nearly as well from the factory as the four holer. This translates into more belt slip and clutch sheave wear happening at lower mileage. The triples also have far more harmonics being transferred to the clutch because a) it’s a triple and b) they’re not attached to a gear-reduced stub offering some “cushion” like the four holer. More clutch maintenance and earlier service intervals are just part of the deal with the triple vs the quad. Go chase the last of the snow fellas.

 

[Apexpat]

Simple, the three bangers aren’t clutched nearly as well from the factory as the four holer. This translates into more belt slip and clutch sheave wear happening at lower mileage. The triples also have far more harmonics being transferred to the clutch because a) it’s a triple and b) they’re not attached to a gear-reduced stub offering some “cushion” like the four holer. More clutch maintenance and earlier service intervals are just part of the deal with the triple vs the quad. Go chase the last of the snow fellas.

Yeah that’s the plan. Back to the UP after this big dump of snow. Guess I better stock up on belts