Interesting clutch stuff, Viper clutches & floating secondary

[KnappAttack]

So a few interesting tidbits as I switched over to my RX-1 primary today along with Viper secondary.

This RX-1 drive clutch sits out further from the engine about 1.5mm. I had to install my circlip back on the shaft to space the Viper secondary away from the bearing 1.5mm further. Good thing because I noticed the bolts that set the deflection on the viper secondary were hitting the alum bearing mount a slight bit when running in OD prior to adding back in the circlip with the winder primary.

The Viper secondary was coil binding badly with even an old stock Yamaha white secondary spring before using full travel of the drive clutch. Even worse was the stock Yamaha winder yellow secondary spring. I ended up using a 49-41 nickle plated Advant-Edge helix that I used on my old 150 track HP turbo Apex that is already cut for OD along with the Dalton black orange. This combo provides basically the same side pressure as a Cat Green spring in a winder roller secondary set at 0-1 on the stock 35 helix. So light springs in the Viper secondary provide more shift out force on my drill press scale than a heavy spring in the Winder roller secondary. Also when "letting off" the pressure is lower on the Viper button secondary than the Winder roller secondary. It provides what the belt needs to prevent slippage when accelerating hard and reduced side pressure on the belt when not running hard, kind of a best of both worlds thing. I can now see why the Viper secondary works better for some and prolongs belt life.

Another thing is the overdrive percentage. Both the Winder and RX-1 stock clutches shift to the same exact point on the primary once you get the button secondary to travel the full distance and not "coil or hub bind", hub being the point on say a stock helix that limits the secondary travel.

The weights and rollers have been moved out away from the post 3mm on the Winder primary vs the RX-1 primary. I always wondered how much they moved them.

Another item I noticed is I set up some float on the secondary initially, 1.75 mm to be exact. I noticed when not on the throttle hard, the secondary moves to where it needs to go to line the belt up perfectly, but here is the kicker and what I've always believed. Under hard acceleration, the secondary DOES NOT move over and align itself! How do I know? Simple, use a little brake on the stand and give it full throttle while holding the brake, mimicking having the track on the snow and under and actual load.

Floating the secondary does not allow for proper belt alignment when under a load! I greased up the shaft real good and it floated real nice and easy, until you put it under power it does not float until you let off the throttle!

So I'm going back to shimming the secondary solid so it lines up properly at 1:1 or OD, I'm not letting it float anymore at all.

Interesting stuff for guys switching clutches or thinking about floating vs. non floating.

Stock RX-1 drive clutch above with Viper secondary & XS825 belt. Same amount of travel as Winder primary. Check marker

Stock winder clutch below with Viper secondary & XS825 belt. Same amount of travel as RX-1 primary. Check marker

 

[sideshowBob]

I am very interested in results with the clutch changes ...keep the info coming!

 

[Fleecer]

When i tested viper secondary years ago. I too mounted it solid and experienced great belt life.

 

[Sledbrapping88]

So a few interesting tidbits as I switched over to my RX-1 primary today along with Viper secondary.

This RX-1 drive clutch sits out further from the engine about 1.5mm. I had to install my circlip back on the shaft to space the Viper secondary away from the bearing 1.5mm further. Good thing because I noticed the bolts that set the deflection on the viper secondary were hitting the alum bearing mount a slight bit when running in OD prior to adding back in the circlip with the winder primary.

The Viper secondary was coil binding badly with even an old stock Yamaha white secondary spring before using full travel of the drive clutch. Even worse was the stock Yamaha winder yellow secondary spring. I ended up using a 49-41 nickle plated Advant-Edge helix that I used on my old 150 track HP turbo Apex that is already cut for OD along with the Dalton black orange. This combo provides basically the same side pressure as a Cat Green spring in a winder roller secondary set at 0-1 on the stock 35 helix. So light springs in the Viper secondary provide more shift out force on my drill press scale than a heavy spring in the Winder roller secondary. Also when "letting off" the pressure is lower on the Viper button secondary than the Winder roller secondary. It provides what the belt needs to prevent slippage when accelerating hard and reduced side pressure on the belt when not running hard, kind of a best of both worlds thing. I can now see why the Viper secondary works better for some and prolongs belt life.

Another thing is the overdrive percentage. Both the Winder and RX-1 stock clutches shift to the same exact point on the primary once you get the button secondary to travel the full distance and not "coil or hub bind", hub being the point on say a stock helix that limits the secondary travel.

The weights and rollers have been moved out away from the post 3mm on the Winder primary vs the RX-1 primary. I always wondered how much they moved them.

Another item I noticed is I set up some float on the secondary initially, 1.75 mm to be exact. I noticed when not on the throttle hard, the secondary moves to where it needs to go to line the belt up perfectly, but here is the kicker and what I've always believed. Under hard acceleration, the secondary DOES NOT move over and align itself! How do I know? Simple, use a little brake on the stand and give it full throttle while holding the brake, mimicking having the track on the snow and under and actual load.

Floating the secondary does not allow for proper belt alignment when under a load! I greased up the shaft real good and it floated real nice and easy, until you put it under power it does not float until you let off the throttle!

So I'm going back to shimming the secondary solid so it lines up properly at 1:1 or OD, I'm not letting it float anymore at all.

Interesting stuff for guys switching clutches or thinking about floating vs. non floating.

View attachment 151555

Stock RX-1 drive clutch above with Viper secondary & XS825 belt. Same amount of travel as Winder primary. Check marker

Stock winder clutch below with Viper secondary & XS825 belt. Same amount of travel as RX-1 primary. Check marker


View attachment 151556

Man hopefully this works out for you and for rest of us this hard on clutch components and belts is getting pricey. This is a little off topic but I think I found part of problem why I blew 2 belts in 100 miles. Well got looking at the sled today one secondary rollers has little chunk out of it. Also noticed that primary sheaves look like they slapped together when belt blew have some rough surface at bottom of the sheaves near clutch shaft. Really hope some one figures these problems out my sled has 690miles on it. I tuned my sled at 630 miles so really 2 belts in 60 miles that's should not happen almost makes me wish I didn't tune my sled bc of waste of money.

 

[Fleecer]

Man hopefully this works out for you and for rest of us this hard on clutch components and belts is getting pricey. This is a little off topic but I think I found part of problem why I blew 2 belts in 100 miles. Well got looking at the sled today one secondary rollers has little chunk out of it. Also noticed that primary sheaves look like they slapped together when belt blew have some rough surface at bottom of the sheaves near clutch shaft. Really hope some one figures these problems out my sled has 690miles on it. I tuned my sled at 630 miles so really 2 belts in 60 miles that's should not happen almost makes me wish I didn't tune my sled bc of waste of money.

Welcome to the jungle!! Lol

 

[ClutchMaster]

Another thing that should be noted about these big power 4 stroke turbo machines is they produce a sinusoidal wave of power to the clutch. A three cylinder two stroke has six combustion events for every 720 degrees of crankshaft rotation. A three cylinder four stroke has only 3 power strokes in 720 degrees of rotation. If both engines produced the same amount of power the four stroke would have much larger spikes in speed and torque, all this needs to be absorbed by the belt and jackshaft.
Jackshaft will twist some helping smooth things out, but if your not clamping the belt hard enough it slips.

I’m really hoping that Timken hasn’t cheapened up the XS belts, they are my go 2 belt! Hard like an 8dn, so low distortion, but they get somewhat sticky when heated up. I’m a little surprised you didn’t try this belt before ditching the roller secondary setup.

 

[KnappAttack]

Another thing that should be noted about these big power 4 stroke turbo machines is they produce a sinusoidal wave of power to the clutch. A three cylinder two stroke has six combustion events for every 720 degrees of crankshaft rotation. A three cylinder four stroke has only 3 power strokes in 720 degrees of rotation. If both engines produced the same amount of power the four stroke would have much larger spikes in speed and torque, all this needs to be absorbed by the belt and jackshaft.
Jackshaft will twist some helping smooth things out, but if your not clamping the belt hard enough it slips.

I’m really hoping that Timken hasn’t cheapened up the XS belts, they are my go 2 belt! Hard like an 8dn, so low distortion, but they get somewhat sticky when heated up. I’m a little surprised you didn’t try this belt before ditching the roller secondary setup.

So true, but same 3 cylinder as Doo's 1200 and I had no trouble clutching that monster. It was faster than a boosted winder too, just didn't handle or ride quite as well as a Winder.

I hope they didn't mess up the XS825 either, and I can easily swap a clutch back into play in just minutes. So no big deal, I do it to test back to back. Piece of cake.

 

[STAIN]

Interesting for sure. I am guessing you will be back within a few degrees +/- of 45 on that secondary when you are done with conversion?
It is strange that these Winder clutches with their different weight/helix diameters seem to be so inconsistent vs the RX-1/Apex clutching, which is rock solid. And the tuning approach makes sense with those older clutch's. There seems to be no rhyme or reason with the new stuff, which is the most frustrating part. Do you suppose there is some flex in those clutch's somewhere?


I am sure in your racing career you must have found the button secondary to be a more consistent performer than the roller?

 

[Beerman]

The professor is back in class! Great info Mike - thanks! Me thinks I need to eliminate the float for sure now.

 

[KnappAttack]

Interesting for sure. I am guessing you will be back within a few degrees +/- of 45 on that secondary when you are done with conversion?
It is strange that these Winder clutches with their different weight/helix diameters seem to be so inconsistent vs the RX-1/Apex clutching, which is rock solid. And the tuning approach makes sense with those older clutch's. There seems to be no rhyme or reason with the new stuff, which is the most frustrating part. Do you suppose there is some flex in those clutch's somewhere?


I am sure in your racing career you must have found the button secondary to be a more consistent performer than the roller?

Yes, absolutely the button clutch was a better performer and more consistent when racing every single time I went back and tested the roller covers.

As we know from running the old button secondary it was never too fussy until given too much helix and then had severe slippage to the point of melting the aluminum sheaves. 45 to 47 degree median was always about right on earlier boosted Yamaha's. Much more than that and the belt could not keep a hold on belts.

As for flex, I don't think so, I believe the helix is just too large to keep a good grip on the belt in high ratio, and/or as we know the roller clutch has no dampening effect, say if the belt has wide and narrow spots in it, so imagine it bouncing on and off the belt at a high frequency perhaps. I've run other roller secondaries with great success, but this winder secondary is a different animal as the helix is much larger which changes everything I think.

The professor is back in class! Great info Mike - thanks! Me thinks I need to eliminate the float for sure now.

I'm not going to be floating the secondary after seeing that anymore either Art. I have no idea why I never checked it like that earlier, but it was quiet telling and what I've always expected that when under power and load that the belt cannot center itself until you let off the throttle.

 

[KnappAttack]

I know its still early in my testing of the old Yamaha clutch combo, but I'm dang stoked with what I see thus far!

Just in from a 50 mile run, broke a XS belt in for 20 miles and was able to find some stretches where it was good. All I can say is I'm very impressed. It seems I hit the mark dang close if not spot on for clutching with the whole switchover to old style primary and secondary clutches. Its warm here and the little bit of snow we have is going fast, 38F degrees and sloppy. It works just as good as it did on my old turboed Apex.

Much improved performance as for consistency hitting RPM run after run and wow are they ever cool. Back to back to back deep snow running after riding and the inner primary 120F, belt 145F and secondary is 90F. I was waiting for the belt to blow because I could have never done that on the big tunes with the winder clutches before in deep fresh sloppy snow. The machine even feels better on the trails and the untracked snow.

I'm running the Timken XS825, RX-1 drive clutch w/15 mm stock rollers, DTYA-1 empty @ 74.9G, 40-131 GGG Yamaha primary spring, Secondary is a Viper button driven (thanks Clutchmaster!), helix is a nickel plated Advant-Edge 49-41 I took from my old 150 track HP Apex turbo (cut way more aggressive than Dalton or stock so equal to about a 53-45 or 51-43 Dalton somewhere in there) and Dalton red Yamaha secondary spring wrapped at 80. The XS belt really drags the RPM down compared to the Yamaha belts and makes the engine work harder with less weight. Maybe as the miles pile on it, the RPM will come up more perhaps, I don't know. Response seems good, I may tighten the secondary up to 90 to make it even better. I just know I like what I'm seeing so far. I run 8750-8800 run after run.

So I've gone a complete 180 from where I was running big primary weights and heavy secondary springs before when using the Winder clutches, to using much lighter components now along with the XS 825 belt. I hope the the old Viper secondary and RX-1 primary will be the answer to us keeping primary rollers and belts on these things for the long run.

I'll also add that I've aligned with Hurricane bar and bolted it down solid for ZERO FLOAT.

Can't wait for it too get cold and snow some more.

 

[sledheadgeorge]

I know its still early in my testing of the old Yamaha clutch combo, but I'm dang stoked with what I see thus far!

Just in from a 50 mile run, broke a XS belt in for 20 miles and was able to find some stretches where it was good. All I can say is I'm very impressed. It seems I hit the mark dang close if not spot on for clutching with the whole switchover to old style primary and secondary clutches. Its warm here and the little bit of snow we have is going fast, 38F degrees and sloppy. It works just as good as it did on my old turboed Apex.

Much improved performance as for consistency hitting RPM run after run and wow are they ever cool. Back to back to back deep snow running after riding and the inner primary 120F, belt 145F and secondary is 90. I was waiting for the belt to blow because I could have never done that on the big tunes with the winder clutches before in deep fresh sloppy snow. The machine even feels better on the trails and the untracked snow.

I'm running the Timken XS825, RX-1 drive clutch w/15 mm stock rollers, DTYA-1 empty @ 74.9G, 40-131 GGG Yamaha primary spring, Secondary is a Viper button driven (thanks Clutchmaster!), helix is a nickel plated Advant-Edge 49-41 I took from my old 150 track HP Apex turbo (cut way more aggressive than Dalton or stock so equal to about a 53-45 or 51-43 Dalton somewhere in there) and Dalton red Yamaha secondary spring wrapped at 80. The XS belt really drags the RPM down compared to the Yamaha belts and makes the engine work harder with less weight. Maybe as the miles pile on it, the RPM will come up more perhaps, I don't know. Response seems good, I may tighten the secondary up to 90 to make it even better. I just know I like what I'm seeing so far. I run 8750-8800 run after run.

So I've gone a complete 180 from where I was running big primary weights and heavy secondary springs before when using the Winder clutches, to using much lighter components now along with the XS 825 belt. I hope the the old Viper secondary and RX-1 primary will be the answer to us keeping primary rollers and belts on these things for the long run.

That's great work. Keep us in the loop.

 

[STAIN]

Impressive results so far. I kind of cringed when I saw you running 75 gram weight on a 270(?) tune BUT we have been throwing weight and springs at these things for a while now trying get rid of slip. I was running 80 grams and CAT green secondary spring when I was using stock clutch's.
If you can get that light spring/weight combo to work and drive out like heavy stuff and not slip, then you will be ahead of the game in terms of efficiency, throttle response and maybe some fuel mileage.
Do you think the lighter components will load the motor enough to make it work? It seems like the four stroke motor likes to be loaded vs. being spun quickly, if that makes sense.
I was going that way for a while( lighter) with my stock clutching but when I started to ramp up the power it all went out the window.
Keep up the good work and keep us posted!!!

 

[KnappAttack]

Impressive results so far. I kind of cringed when I saw you running 75 gram weight on a 270(?) tune BUT we have been throwing weight and springs at these things for a while now trying get rid of slip. I was running 80 grams and CAT green secondary spring when I was using stock clutch's.
If you can get that light spring/weight combo to work and drive out like heavy stuff and not slip, then you will be ahead of the game in terms of efficiency, throttle response and maybe some fuel mileage.
Do you think the lighter components will load the motor enough to make it work? It seems like the four stroke motor likes to be loaded vs. being spun quickly, if that makes sense.
I was going that way for a while( lighter) with my stock clutching but when I started to ramp up the power it all went out the window.
Keep up the good work and keep us posted!!!

I couldn't agree more. I've never liked the fact I had to keep going stiffer and stiffer in the secondary and heavier in the primary weights, quite the contrast to what I'm used to doing with this thing for sure. I'm amazed at how light the secondary actually is, but this is where I ran it in my old 150 track HP Turbo Apex too, and that was with the 8DN belt, so I believe using the XS 825 we can get by pinching it far less. There comes a point where pinching the secondary to grab the belt will bite a guy, and I found that point last season when the temps would warm up.

I didn't have good consistent performance with the Winder clutches and heavier secondary. It would be perfect one day, the next it'd warm up and I was smearing the belt again. I had to do something, because I've been trying to find perfection for years with it and could never say I hit it perfect for all conditions.

I'm going to tell you I'm loading the engine harder than ever with this setup, almost a wee bit too much, but I figure when the air temps cools down and perhaps when the belt wears in a bit more, I'll actually be adding some weight to the arms back in. I know its early, but I'm seeing great promise as it does not let go of the belt up top like I had been seeing with the Winder clutches and struggling with on the big tunes. The clutches look perfect, but lets see what it does as the miles rack up. At least its acting like a normal turbo snowmobile now. I'm amazed at how cool everything really runs beating the tar out of it. Nice to be able to open the secondary with minimal pressure at rest.

 

[STAIN]

How does throttle response compare? Did you find the throttle getting lazy with heavy weights?