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

[KnappAttack]

Nice info Mike and thanks for your work and feedback....

Things make more sense now, as Ive been running the Hi-Torque rollers since the beginning, as Ive always liked their fiber design. I guess this is why you and I end up with diff results using similar tunes. This type of testing and understanding of our tunes and how they make power and put power down is priceless, great work.

Mike, I dont recall if you tested at all with the Xs825, but if you have I'd like to hear about that and how it fits into your thoughts. I gave up on the 8JP too(last season) and I do have 2 8DNs here and a 22 tooth to mess with. But in the end, the Ultimax for me works well. I now worry more about other deficits in engineering on these sleds, as I contemplate a BIG trip right from my door.....Hard to be confident in this sled after the last tow rope incident.

Dan

Don't fix it if it ain't broke Dan.

If you have a clutch combo you are happy and like, stick with it. I have a couple XS805's here which are the 8DN replacements, but I find them a bit long and the deflection a bit loose as my driven won't close any further for them to get the deflection any tighter.

I have had great success with the 8DN and making the changes needed for it. It runs fairly cool and lays the power down better and much more consistently than the 8JP for my setup. I plan to stick with it and not stray away unless I have problems in the future I can't foresee now.

I know for me they seem softer as they are a fiber, and mine are now 'worn in' since season one. Sounds like Mike is saying they roll easier since it lost rpms. Maybe they are larger OD by a tad? I always run them, my OSP rollers I tried initially are super hard surface and could actually slide on the ramp(not roll) and why I like the Hi-Torque, since they ride so nice and smoothly on ramp.

I know Im often less grams then Mike, and now realize why....Good to see this came up in Mike's testing, I never would have thought so either.

Dan

Dan, I first saw it on the bench after assembling the clutch and pressure testing and cycling it in my drill press again on the scale. The Hi-Torques are very good at reducing friction and allowing secondary clutch to shift very smoothly to say the least. It was like going from an old button clutch to a roller clutch for smoothness. It was plain to see that it was going to affect the shifting using heavier secondary springs especially, I just didn't realize how much it was going to affect it. I can compensate for the rollers by making clutch changes, which I might do yet, the jury is still out on this one. For now the old rollers are back in from the testing and riding I did yesterday.

 

[jonlafon1]

I actually dropped a set of FETT brother rollers in recently.. They are fiber material with the washer installed next to them.. Very interesting that this would effect things.. I have said it many times but > these secondary clutches and three rollers are very sensitive to spring pressure AND HELIX angle. Obviously a bunch of other factors involved but what Knapp found is proof they are sensitive to minor changes.. Another thing mentioned is if its working dont mess with it... Im chasing my setup slightly at this point as i made changes. Slightly more HP, 22 top gear and the fun has started! At least we got snow to test. On secondary spring number 2 .. And still twisting before each ride. getting close now!

 

[STAIN]

Were the old button secondary that bad? They were more consistent thats for sure.

 

[KnappAttack]

Were the old button secondary that bad? They were more consistent thats for sure.

Bad. No way were they bad, quite the opposite in fact. Buttons are what most of what the drag racers run in fact.

Just the fact that with a roller vs button, there is about a 8-10 degree difference in helix angle change needed.

 

[ClutchMaster]

Bad. No way were they bad, quite the opposite in fact. Buttons are what most of what the drag racers run in fact.

Just the fact that with a roller vs button, there is about a 8-10 degree difference in helix angle change needed.

I think he was being sarcastic

 

[PowderFalcon]

I ran the cat green spring today with 37/35 helix at 0/1 wrap. Both clutches were super hot and could feel belt slip . Couldn’t touch them. Backed it off to 9/1. Still hot but could hold my hands on them

 

[STAIN]

What is your tune? What is your primary set up? You are slipping the primary, right? If you run a heavy secondary spring then you need heavy primary weights to open the secondary.
That Cat green is pretty stiff. I run one on a 270 tune with a 35 degree helix. I towed TWO sleds at ONCE yesterday in wet snow and did not slip the belt.

 

[ClutchMaster]

I ran the cat green spring today with 37/35 helix at 0/1 wrap. Both clutches were super hot and could feel belt slip . Couldn’t touch them. Backed it off to 9/1. Still hot but could hold my hands on them

It’s not slipping your actual too tight on the belt

 

[Doowithblue]

Hey guys are the tangs same with cat green vs dalton white? Maybe this will help clear the air here.

 

[KnappAttack]

Yesterday was an extremely good day on the trails for me. I'm honing in on clutching nirvana for my machine. Went back to the stock Yamaha secondary rollers and was able to put the weight back into the clutch arms. I messed around going back the the Dalton black/orange driven spring for a bit last week and no workie for me with either a 8JP or the 8DN, just like last year, slippage in the secondary, I could even smell the belt at times. I just can't run light weights or light driven spring setups on the big tunes, on the 240 its fantastic, but any more than that and I just can't. They just don't grip the belts for me, no way, no how. I corded a 8DN belt because I tried the light stuff again, the heat was so immense I end up with over 225* primary and belt temps after just one run trying it!

The heavy setup I can achieve extremely low clutch and belt temps using the 8DN. I'm up to 82.2 G in the Daltons and need more yet to keep RPM in check using the EPI purple set at 0-1. I keep putting more weight in on the 290R tune and it just keeps asking for more. My gosh am I loving this sled now! Going to end up at 83.5G in the Dalton arms today. The 8DN is holding up great now that I put the heavy package back in with the Yamaha secondary rollers. My god is this sled fast! No more light secondary springs, light weights or 8JP's for me anymore. I can finally say WOW, I am very happy, happy, happy with this sled now!


For those trying to run heavy springs on soft belts and getting hot temps, well that may not work that great and it may need a belt like the 8DN to work properly, I believe the whole package needs to work together as a team, even though you think you are running the correct RPM, that means nothing to the system performing as it should. I tried my setup with just a different set of secondary clutch rollers that shifted smother and faster, I had to lighten up the primary arms, I was too light on the arms up front at 78G and couldn't keep a hold on the belt in the primary at that point, I was chasing my tail. All I did was take out those rollers and go back to the stock Yamaha secondary rollers and put the weight in the arms and I got the balance back where the system was happy again. You just need to find that window where the primary, the secondary and belt are happy together.


On another note: I found using earplugs masks the clutch rattle, the exhaust and the wind noise. Imagine that.

 

[74Nitro]

Yesterday was an extremely good day on the trails for me. I'm honing in on clutching nirvana for my machine. Went back to the stock Yamaha secondary rollers and was able to put the weight back into the clutch arms. I messed around going back the the Dalton black/orange driven spring for a bit last week and no workie for me with either a 8JP or the 8DN, just like last year, slippage in the secondary, I could even smell the belt at times. I just can't run light weights or light driven spring setups on the big tunes, on the 240 its fantastic, but any more than that and I just can't. They just don't grip the belts for me, no way, no how. I corded a 8DN belt because I tried the light stuff again, the heat was so immense I end up with over 225* primary and belt temps after just one run trying it!

The heavy setup I can achieve extremely low clutch and belt temps using the 8DN. I'm up to 82.2 G in the Daltons and need more yet to keep RPM in check using the EPI purple set at 0-1. I keep putting more weight in on the 290R tune and it just keeps asking for more. My gosh am I loving this sled now! Going to end up at 83.5G in the Dalton arms today. The 8DN is holding up great now that I put the heavy package back in with the Yamaha secondary rollers. My god is this sled fast! No more light secondary springs, light weights or 8JP's for me anymore. I can finally say WOW, I am very happy, happy, happy with this sled now!


For those trying to run heavy springs on soft belts and getting hot temps, well that may not work that great and it may need a belt like the 8DN to work properly, I believe the whole package needs to work together as a team, even though you think you are running the correct RPM, that means nothing to the system performing as it should. I tried my setup with just a different set of secondary clutch rollers that shifted smother and faster, I had to lighten up the primary arms, I was too light on the arms up front at 78G and couldn't keep a hold on the belt in the primary at that point, I was chasing my tail. All I did was take out those rollers and go back to the stock Yamaha secondary rollers and put the weight in the arms and I got the balance back where the system was happy again. You just need to find that window where the primary, the secondary and belt are happy together.


On another note: I found using earplugs masks the clutch rattle, the exhaust and the wind noise. Imagine that.

Hi Mike, what gas are you running? I was out yesterday and today and triggered the knock light on about 1/4 mile pull on either 275 or 290. Maybe I just got some crap 91.

 

[KnappAttack]

Hi Mike, what gas are you running? I was out yesterday and today and triggered the knock light on about 1/4 mile pull on either 275 or 290. Maybe I just got some crap 91.

91 with a splash of Dragon concentrate booster, but I've been filling up with straight 91 or 92 and its been fine however.

 

[PowderFalcon]

It’s not slipping your actual too tight on the belt

I switched to 9/1 and it wasn’t as hot but still not great. Should I go softer wrap yet?

 

[74Nitro]

Yesterday was an extremely good day on the trails for me. I'm honing in on clutching nirvana for my machine. Went back to the stock Yamaha secondary rollers and was able to put the weight back into the clutch arms. I messed around going back the the Dalton black/orange driven spring for a bit last week and no workie for me with either a 8JP or the 8DN, just like last year, slippage in the secondary, I could even smell the belt at times. I just can't run light weights or light driven spring setups on the big tunes, on the 240 its fantastic, but any more than that and I just can't. They just don't grip the belts for me, no way, no how. I corded a 8DN belt because I tried the light stuff again, the heat was so immense I end up with over 225* primary and belt temps after just one run trying it!

The heavy setup I can achieve extremely low clutch and belt temps using the 8DN. I'm up to 82.2 G in the Daltons and need more yet to keep RPM in check using the EPI purple set at 0-1. I keep putting more weight in on the 290R tune and it just keeps asking for more. My gosh am I loving this sled now! Going to end up at 83.5G in the Dalton arms today. The 8DN is holding up great now that I put the heavy package back in with the Yamaha secondary rollers. My god is this sled fast! No more light secondary springs, light weights or 8JP's for me anymore. I can finally say WOW, I am very happy, happy, happy with this sled now!


For those trying to run heavy springs on soft belts and getting hot temps, well that may not work that great and it may need a belt like the 8DN to work properly, I believe the whole package needs to work together as a team, even though you think you are running the correct RPM, that means nothing to the system performing as it should. I tried my setup with just a different set of secondary clutch rollers that shifted smother and faster, I had to lighten up the primary arms, I was too light on the arms up front at 78G and couldn't keep a hold on the belt in the primary at that point, I was chasing my tail. All I did was take out those rollers and go back to the stock Yamaha secondary rollers and put the weight in the arms and I got the balance back where the system was happy again. You just need to find that window where the primary, the secondary and belt are happy together.


On another note: I found using earplugs masks the clutch rattle, the exhaust and the wind noise. Imagine that.

 

[74Nitro]

I've always been a fan of the 8DN. I switched to it last year after blowing the 8JP at only 380.onef the guys a ride with blew his original 8jp on his then new 17 at only 83 kms! I also don't miss the belt dust. One of the cheapest belts also(if not the cheapest). What's not to like.