Blew Belt, Sheared Primary Bolt Off, 2 XS825 Belts Gone in ~160 miles

[kinger]

View attachment 153271 325 mi on this 8DN Tapp/pro4 combo. Extreme full throttle to full brake corner to corner trail riding, came out into a field, whacked it then BAM. Tapp runs cool to ever so slightly warm, Pro4 very warm, but can hold hand on it. Combo is smooth as hell when riding but belt life is definately concerning.

That is concerning. a 300+ apex on 8DN lasted 5000 miles and only replaced because it was 6 years old. I don't think its the power. I wish I could get a scientific rating on the belts "TQ limit". That said something else seems a miss in the design of the winder clutches, and drivetrain. I rode the apex hard too, similar to you it was a blast! I could stretch the chain in the chaincase every 500-1000 miles landing on jumps and other stuff. The 8DN belt never blew though. I was hoping this would be the solution for the winders was optimizing for the 8DN belt. Bummer

 

[STAIN]

What you do is clean both the shaft and inside clutch surfaces and apply a bit of valve lapping compound to one surface or the other, then apply pressure to the clutch while spinning it on the shaft to provide a perfect fit so they can mate up over the entire surface they are supposed to seat on. Once this is done clean off both surfaces and bolt the clutch on. But on the 998, only spin the clutch in the direction the engine would run as to make sure not to turn the crankshaft backwards, possibly having the exhaust cam come out of time.

Valve lapping compound has abrasives in it, so it would be like sanding both sides to a perfect fit to one another rather than sitting on high spots. This prevents the clutch from spinning on the shaft or perhaps coming off the shaft if the bolt broke.

Just do this to the clutch and shaft rather a valve and head.

Another thing that you can do after the lapping process is take you MAP gas torch and heat the inside of the clutch, the tapered part. Dont get carried away, just heat enough so that when you install the metal shrinks a bit on the stub shaft giving it a bit more of a secure fit.

 

[STAIN]

What you do is clean both the shaft and inside clutch surfaces and apply a bit of valve lapping compound to one surface or the other, then apply pressure to the clutch while spinning it on the shaft to provide a perfect fit so they can mate up over the entire surface they are supposed to seat on. Once this is done clean off both surfaces and bolt the clutch on. But on the 998, only spin the clutch in the direction the engine would run as to make sure not to turn the crankshaft backwards, possibly having the exhaust cam come out of time.

Valve lapping compound has abrasives in it, so it would be like sanding both sides to a perfect fit to one another rather than sitting on high spots. This prevents the clutch from spinning on the shaft or perhaps coming off the shaft if the bolt broke.

Just do this to the clutch and shaft rather a valve and head.

Another thing that you can do after the lapping process is take you MAP gas torch and heat the inside of the clutch, the tapered part. Dont get carried away, just heat enough so that when you install the metal shrinks a bit on the stub shaft giving it a bit more of a secure fit.

 

[NYTurbo]

what is your offset ?

 

[WinterWolf]

I think the point crossfire is making is that the brakes were locked, and the secondary was not given time to shift back,(because it wasn't turning), and then the throttle is hammered while the belt has some slack.

That's exactly what he meant, and I was meaning that same thing too. These Winders have so much torque, and tuned they have even more...they can snap a belt at will in a situation like you stated above like a match stick! Period.
Lock the brake and the Secondary didn’t back shift cuz it’s locked/not spinning..and then mat-it immediately with the slack in the belt ...and you can easily snap any belt on these tuned monsters! That’s the point we were making.

 

[ClutchMaster]

I run more helix than that with no issues in 4000 plus miles. How does this spring compare to the arctic/STM green? One thing I would say is that anytime I veered from that green spring in the secondary, didn't like the results. But its not that his helix is too much, more likely it's not enough. Only the 32 I finally ended with kept the heat in the secondary low enough.

TCat I have run the 46/36 and the 46/38 with the green cat spring with STM secondary and it’s still too much belt tension with the XS belt.
I’m currently testing the EPI purple.
After some years of messing with my setup and listening to what other members have done on this site, I realize that I’ve been too heavy in the primary.
Your primary was pushing to hard and shifting out too fast so going to a lower helix did help the heat issue too a point. If you would have lightened up on your weight, and used a stiffer finish on your primary spring those temps would have dropped also.
The helix you have would be a better choice with the EPI purple and light wrap, pulling a ton of weight out of the primary.
Look at Winter wolf’s setup, he is 7 grams lighter than you?

It was the extreme full throttle full brake and then hammer it again, with all this HP. That’s why the belt broke, try that with your car a bunch of times and see how the tranny holds up!!!! RIDE it like a four stroke not a two stroke and you will save on belts.

Naw that’s malarkey, I ride my junk like I stole it, sure it will reduce belt life but not that extreme. Even if you ride the brake, your pads will overheat and crumble before you snap a belt on a good setup.

That's exactly what he meant, and I was meaning that same thing too. These Winders have so much torque, and tuned they have even more...they can snap a belt at will in a situation like you stated above like a match stick! Period.
Lock the brake and the Secondary didn’t back shift cuz it’s locked/not spinning..and then mat-it immediately with the slack in the belt ...and you can easily snap any belt on these tuned monsters! That’s the point we were making.

There is some truth here, if you lock the track up and don’t release then hit the gas with the brake still applied yer gonna fu€k #*$&@ up, heck you can mess up a belt on a 600cc machine doing this. As for hard on and off the gas riding tho it shouldn’t matter.
LET OFF THE BRAKE FOR 1/2 A SECOND, then smash it 2 the bar.

 

[WinterWolf]

TCat I have run the 46/36 and the 46/38 with the green cat spring with STM secondary and it’s still too much belt tension with the XS belt.
I’m currently testing the EPI purple.
After some years of messing with my setup and listening to what other members have done on this site, I realize that I’ve been too heavy in the primary.
Your primary was pushing to hard and shifting out too fast so going to a lower helix did help the heat issue too a point. If you would have lightened up on your weight, and used a stiffer finish on your primary spring those temps would have dropped also.
The helix you have would be a better choice with the EPI purple and light wrap, pulling a ton of weight out of the primary.
Look at Winter wolf’s setup, he is 7 grams lighter than you?



Naw that’s malarkey, I ride my junk like I stole it, sure it will reduce belt life but not that extreme. Even if you ride the brake, your pads will overheat and crumble before you snap a belt on a good setup.


There is some truth here, if you lock the track up and don’t release then hit the gas with the brake still applied yer gonna fu€k #*$&@ up, heck you can mess up a belt on a 600cc machine doing this. As for hard on and off the gas riding tho it shouldn’t matter.
LET OFF THE BRAKE FOR 1/2 A SECOND, then smash it 2 the bar.

Yup..that’s what I do..I let the secondary catch up/back shift for a second, and then I’m not worried about mashin it.

 

[Tcat100]

TCat I have run the 46/36 and the 46/38 with the green cat spring with STM secondary and it’s still too much belt tension with the XS belt.
I’m currently testing the EPI purple.
After some years of messing with my setup and listening to what other members have done on this site, I realize that I’ve been too heavy in the primary.
Your primary was pushing to hard and shifting out too fast so going to a lower helix did help the heat issue too a point. If you would have lightened up on your weight, and used a stiffer finish on your primary spring those temps would have dropped also.
The helix you have would be a better choice with the EPI purple and light wrap, pulling a ton of weight out of the primary.
Look at Winter wolf’s setup, he is 7 grams lighter than you?

 

[Tcat100]

I run the stiffer primary spring which actually accounts for most of that difference (I've experimented...). Clutchmaster been doing this a long time too. Works great for me.

 

[ClutchMaster]

I run the stiffer primary spring which actually accounts for most of that difference (I've experimented...). Clutchmaster been doing this a long time too. Works great for me.

190 degree belt isn’t great, your on the ragged edge of failure.

I think it’s safe to say a lot of guys on here have been clutching for many years, racing ect. This Big power/roller secondary has fooled a lot of guys, not for lack of trying either.

I also think it’s safe to say you have a lot more belt tension than than me and many others who are using using the XS belt.

fyi last season my buddy tuned hurricane 290 hp sled , he decided to put on the stm primary and secondary clutches , he started out with a 44/38 helix with the green arctic spring . he's secondary was so hot u could not touch it , once he went with a weaker spring (epi purple spring ) helped with lower temp on his secondary , I agree with mike knapp the black /purple is over kill ,

Perfect example right here^^^^^
Heck with that 43/32 yer running I would bet that would work with the cat red/white secondary spring, possibly the yellow spring.

My temps never get over 160 degrees and I’m still not happy at all. I’ve been grinding theses weights every year, time to grind some more. This ain’t no 8dn belt, that’s for sure.

And I call myself Clutchmaster...I should be ashamed it has taken so long to figure out!

 

[J & J Racing]

Bump up finish on helix
I agree with clutch master
If you are running that secondary I would run a minimum of 36 finish. With that the green spring is going to be at softest setting. I ran 38 and 40 finishes with that clutch
With my team setup I really don’t see much above 150 for temps
300 hp tune
Good luck and

ouch on the picture of that clutch

 

[Tcat100]

190 degree belt isn’t great, your on the ragged edge of failure.

I think it’s safe to say a lot of guys on here have been clutching for many years, racing ect. This Big power/roller secondary has fooled a lot of guys, not for lack of trying either.

I also think it’s safe to say you have a lot more belt tension than than me and many others who are using using the XS belt.




Perfect example right here^^^^^
Heck with that 43/32 yer running I would bet that would work with the cat red/white secondary spring, possibly the yellow spring.

My temps never get over 160 degrees and I’m still not happy at all. I’ve been grinding theses weights every year, time to grind some more. This ain’t no 8dn belt, that’s for sure.

And I call myself Clutchmaster...I should be ashamed it has taken so long to figure out!

It's really curious to me why you don't think what I run works well. I'm not going to argue with you about why my setup works for me. Others here can take it or leave it, which they seem to do, but somehow that's a struggle for you. Yet you don't seem to be happy with your setup, but I'm happy with mine? Strange...

I will point out that my razorback temps can't be compared to your gun ones period. If you go on the razorback site you'll see that under 200 is ok, that's why it has a green light. When you measure 160 on your gun once it's stopped, that means it was hotter before you stopped. I would definitely recommend to anyone who does serious trail riding to get the razorback...it works awesome.

 

[J & J Racing]

I run a Razorback
it is nice to compare your changes

I have never heard of anyone running a finish as low as you. To each their own though.
Island
I would run a 46 36 or 46 38

 

[Crossfire12]

I have to disagree. If you cant ride like this without cooking a belt, your clutching calibration is incorrect. If you break an xs825 period, your clutching is off. Its not the power. We run 8JP belts on our turbo viper, pulls 1.1 60 foot times on the TD GPS , 420++hp. We can do 100 passes on a belt without breaking it. Hot lapped it countless times during testing and racing.

A well setup car can launch hard 1000s of times without breaking things.

I agree with your statement, just try 400 hp down a drag strip and at the end slam brakes on full and then hit throttle full bet you will snap it. Your belt will never back shift back up.

 

[jonlafon1]

Under 200 temps is a general statement. And certainly okay. But no way will anyone get any kind of belt longevity at 190, 180. NO WAY. 150 or less and ideally even maybe 130 or less. It certainly won’t matter if your using real time heat numbers or a gun at 180 or more.