Interesting clutch stuff, Viper clutches & floating secondary

[KnappAttack]

Mike, I’m running a 48-40 Advantage-Edge with Yammy white spring at 60* in the old button clutch......your saying it will cool bind badly at full shift? I was led to believe that they cut their helixes to enable a little more overdrive with the right set up, but also machined the spring pocket area enough to avoid binding issues. I’ve never checked for it myself.

Although the Advant-Edge helix is cut on the hub for OD fine, the Yamaha white spring still coil binds before the drive clutch brings the belt fully to the top set at 60*. I had to add .060" shims under the helix, (which I hate doing) to keep that combo from coil binding completely under the Advant-Edge.

 

[KnappAttack]

Stock SW clutches . personally i have never been able to get more than 0,93 overdrive
View attachment 152033





Good OLD school. I have removed 0,030 to each sheaves . I think i am gona be able to get 0.88 out of them .
Testing next week!

View attachment 152034

.020" in belt width was equal to 2% more OD in my old Cats as I recall. It was certainly nice seeing what I had with the on-board computer in regards to engine and jackshaft RPM. With the onboard data acquisition computer you could easily see the amount of OD you were getting without guessing. So .030" I'd say you would get another 3% or in that ballpark. Just make darn sure the secondary will go that far open. I think you are beyond using the 8JP length belts here, you would do yourself a favor going to the longer 8DN belt length if you are going to do that added OD in the primary. The reason is, using the stock primary on the 8JP length belt it is already using all available secondary travel in the stock sheaves, so its going to need a longer belt and start higher in the secondary to keep from running out of travel there. If you try to push it using 8jp lengths, the belt will run off the bottom of the angle on the secondary, and you do not want the cogs below the angle on the sheaves at all, severe slippage and bad things will occur.

Can you tell I've been down this road before a time or two?

 

[Big_Phil]

Just a thought, I know one member here mentioned he switched his Winder to 15mm rollers, and has had success without issue ever since. Not sure who it was, but could just having a larger OD roller be the fix, at least for roller life?

Dan

15.5mm rollers from a Viper clutch on my winder. 8000kms on the rollers now, and they were off a used, but low mile, viper clutch. Still look good. 270+ hp since day I got the sled, around 12000kms on the stock clutches now.

 

[jonlafon1]

Had real good luck with primary rollers? Stock size that is. BUT I do not run heavy weights. Running 68 gram TP heavy hitters. Zero issues with rollers or anything else in primary. Heavy flat profile weights will eat rollers way faster then a more aggressive lighter curved weight. Surely I will be called out on this but so be it. I’m betting I run less weight then anyone on here with powertrail tune. My point is you do not have to run massive amounts of weight in the stock primary to make it work. And maybe the heavy flat weights are what eat stock roller size?

 

[Stubbs]

15.5mm rollers from a Viper clutch on my winder. 8000kms on the rollers now, and they were off a used, but low mile, viper clutch. Still look good. 270+ hp since day I got the sled, around 12000kms on the stock clutches now.

Is your Winder chewing up the STM weights like your Nytros did, or are they lasting in this new clutch?

 

[74Nitro]

Had real good luck with primary rollers? Stock size that is. BUT I do not run heavy weights. Running 68 gram TP heavy hitters. Zero issues with rollers or anything else in primary. Heavy flat profile weights will eat rollers way faster then a more aggressive lighter curved weight. Surely I will be called out on this but so be it. I’m betting I run less weight then anyone on here with powertrail tune. My point is you do not have to run massive amounts of weight in the stock primary to make it work. And maybe the heavy flat weights are what eat stock roller size?

I would think that either of those scenarios would exert the same amount of force on the roller, no?

 

[jonlafon1]

I would think that either of those scenarios would exert the same amount of force on the roller, no?

78-80 grams vs 67-69 grams. Different profile also. IMO not the same force. One thing I notice is the distance from the roller to the weight. Seems like a lot. When engaged it’s on the roller but as you engage the sheaves and disengage the roller is being contacted by the weight. I would think the bigger diameter roller could take some of this shock away? Not disagreeing with larger rollers as maybe it’s the way to go with running heavy weights? I just see minimal roller wear on 68 gram TP heavy hitters.

 

[KnappAttack]

I would think that either of those scenarios would exert the same amount of force on the roller, no?

Well on the belt yes it would, but with the rollers and pressure against the roller its kind of a different situation. Its about the angle you are hitting the rollers at compared to the arm, and the weight needed to force the roller and weight into the belt. It might be better to explain it in different and simple terms, so imagine for a moment just using a wedge between the rollers and the movable. You have two wedges to chose from, one a 90 wedge, and another 45 degree wedge, both will move the movable, but with the 45 degree wedge it will put less stress on the roller and move further dong the same work with less angle, the force on the roller is more efficient when you are working more inline with the travel of the movable rather than the travel that is away from the movable.

Flatter weights want to blow the roller outward with less angle and more weight, more aggressive weights apply more pressure towards the belt with less weight when upshifting, but other factors also come into play such as deceleration and back shift. The trick is finding the compromise to get the best of what you are looking for. When four-strokes came out there was advantages to flatter weights that came to light that overcame purely aggressive upshift two-stroke weights. The flatter weight will untuck better right from engagement applying more force where the four-stroke makes enough power (TQ) to burn the belt on the other weighs. Dalton for instance has a compromise between the two on the curvature, but its all about the angle they are at on the roller and how much force is being applied at any certain point during the shifting.

 

[jonlafon1]

Well on the belt yes it would, but with the rollers and pressure against the roller its kind of a different situation. Its about the angle you are hitting the rollers at compared to the arm, and the weight needed to force the roller and weight into the belt. It might be better to explain it in different and simple terms, so imagine for a moment just using a wedge between the rollers and the movable. You have two wedges to chose from, one a 90 wedge, and another 45 degree wedge, both will move the movable, but with the 45 degree wedge it will put less stress on the roller and move further dong the same work with less angle, the force on the roller is more efficient when you are working more inline with the travel of the movable rather than the travel that is away from the movable.

Flatter weights want to blow the roller outward with less angle and more weight, more aggressive weights apply more pressure towards the belt with less weight when upshifting, but other factors also come into play such as deceleration and back shift. The trick is finding the compromise to get the best of what you are looking for. When four-strokes came out there was advantages to flatter weights that came to light that overcame purely aggressive upshift two-stroke weights. The flatter weight will untuck better right from engagement applying more force where the four-stroke makes enough power (TQ) to burn the belt on the other weighs. Dalton for instance has a compromise between the two on the curvature, but its all about the angle they are at on the roller and how much force is being applied at any certain point during the shifting.

What he said. Yes

 

[Big_Phil]

Is your Winder chewing up the STM weights like your Nytros did, or are they lasting in this new clutch?

Weights still look good. My Nytro had the 50Y weights, which are narrower than the 60Y for the winder.

 

[Stubbs]

Weights still look good. My Nytro had the 50Y weights, which are narrower than the 60Y for the winder.

You’re using the old school weights with lots of profile correct, not the new flatter weights?

 

[Big_Phil]

N

You’re using the old school weights with lots of profile correct, not the new flatter weights?

I am not sure which are which. New ones I assume. I bought them from Hurricane when I got my sled in the fall of 17.

 

[Stubbs]

N


I am not sure which are which. New ones I assume. I bought them from Hurricane when I got my sled in the fall of 17.

The 60y weights have been around quite a while, and have a lot of profile. STM developed these early on in the Apex days. The 60ys weights are newer, developed for the Winder, and have far less profile, more like the 8es Yammy weights but with the all adjustability STM cam arms offer. Both profile of weights can be tuned to work well with big power. Some guys like all the profile they can get, others seem to like a little less curvature and more weight.

 

[Big_Phil]

The 60y weights have been around quite a while, and have a lot of profile. STM developed these early on in the Apex days. The 60ys weights are newer, developed for the Winder, and have far less profile, more like the 8es Yammy weights but with the all adjustability STM cam arms offer. Both profile of weights can be tuned to work well with big power. Some guys like all the profile they can get, others seem to like a little less curvature and more weight.

they are the 60Y. Just checked. I was having issues with belts only lasting 500km with the stock helix, but per clutchmasters suggestion on here, I’m running a 41-37 right now, and I got over 1000kms to my last 8jp last season and it still looks mint. I just put 500kms on an xs825 this week and the belt looks mint still.

 

[snowbeast]

they are the 60Y. Just checked. I was having issues with belts only lasting 500km with the stock helix, but per clutchmasters suggestion on here, I’m running a 41-37 right now, and I got over 1000kms to my last 8jp last season and it still looks mint. I just put 500kms on an xs825 this week and the belt looks mint still.

Phil,did you keep same ramps in for the 825 belt vrs the 8jp stocker? Or have to reduce the amount of weight for that belt?