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

Mine is bone stock still and I have 5100 and change on the odometer. No belt issues yet. I towed a guy in for 20 miles too this week.
 

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 remember an article in Snowtech Magazine from many years ago when Randy Nouis was comparing roller vs button clutches. The number he settled on was 4 deg additional angle that a roller needed over a button to be equal.
 
I remember an article in Snowtech Magazine from many years ago when Randy Nouis was comparing roller vs button clutches. The number he settled on was 4 deg additional angle that a roller needed over a button to be equal.

I found more than double 4 degrees on the race track! I'm sure it depends on the power and conditions you are running. We were able to get a roller secondary setup down to the E.T. of the button if the traction was good. If you spun at all though on the pass, the roller would overshift dramatically and not recover well. Hence the reason you see drag racers using button clutches.
 
Cat green! $50 spring $100 belt. Garbage!

Ran it at 0,1 which was super hot. Then today ran it 9,1. POW 8dn grenade

Back to square 1 I guess
 
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.
What primary spring you running
 
Cat green! $50 spring $100 belt. Garbage!

Ran it at 0,1 which was super hot. Then today ran it 9,1. POW 8dn grenade

Back to square 1 I guess
What is your tune and primary set up? You need horsepower and heavy clutch weights to run that cat green
 
I have not used the STM weights that much. What is your total weight per arm?
 
Blew my second belt bone stock sled about 11oo miles now. Was doing 4 or 5 miles near wot on freshly covered hard pack. The belt was so hot I couldnt hold it in my bare hands. I guess I need to order the alignment tool. Not happy.
 
Running cat green spring at 6,3 now. Not as hot as 9,1 but still too hot for my liking. Going to try 6,2 next.
 
78 grams per arm.

60 base , 7 heel, 4 mid, 7 tip
Brent,try your stock primary or a spring that is close to that,and remove weight off the heel,and run mid empty,add weight to tip,and try again. Where are your rpms with those ramps? I have had best luck with them at a washer on each side in heel,mid empty,and tip one tungsten and on other side 3 washers,gives me 8700 plus,and 38 stm helix cat white at 9-1
 
Brent,try your stock primary or a spring that is close to that,and remove weight off the heel,and run mid empty,add weight to tip,and try again. Where are your rpms with those ramps? I have had best luck with them at a washer on each side in heel,mid empty,and tip one tungsten and on other side 3 washers,gives me 8700 plus,and 38 stm helix cat white at 9-1


Thanks Pete. I’ll havw a look at that!
 
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
Not slipping.....too much backpressure is making heat IMO

Mine did same.
Dan
 


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