Found our missing power.

[stingray719]

I have heard a lot of good things about you sting. We should get in touch before next season, love to head to Colorado. You in Terry?

Check out this webcam at my favorite riding place. 800 square miles of this! Went last Thanksgiving to three feet of new snow and looks to be rideable till end of April.


http://coloradolivecams.com/colocam-grandmesa1.htm


OOps, sorry for getting off topic.

Damn! That looks like fun!

I've been out to that area several times. Hopefully riding some day. Drive from NY to Denver then head south at Glenwood Springs through Carbondale, Paonia, to Hotchkiss. Then into the West Elk Wilderness. Beautiful area.

They rent sleds up there, stop and ride next time. If ya rent from Grand Mesa Lodge the owner will map out the best places to go. Or ping me and I will go!

 

[blade072]

Its lost in the clutch, the primary actually. After the 8DN debacle I went to work studying why this sled was so different from the Nytro clutches. I noticed our Viper came with a 2 stroke profile in the weight. That being a bump in the heel to raise take off revs (as 2 stroke have high horsepower not torque) and then a level ramp for about a third of the profile then a steeper ramp to raise rpm. And yes, why? This is a torque motor not a 2 stroke. I put the flat profile Nytro weights in (Matt from MPI suggested this, and this is what I did to our other boosted Yamahas so it wasn't anything new) and cut to desired rpm and that helped but it still seemed like something was missing. I mean this sled is a lot lighter than a Nytro and should be faster. So I came up with a bizarre test that worked.

All tests with flat profile 8FS weights cut down to 50 grams for above 10k altitude running. Weather about 25 degrees 3 inches snow on top of crust at 10k altitude. Race against 2008 Nytro with Can and a few add ons and a 2012 Nytro with 190hp Turbo


1. Stock clutches - Primary spring 35 open, 101 Shift -----------------------------------------------------Viper slightly slower than Nytro, Turbo blows it away

2. Stiffest primary spring made for this clutch (that I could find) Primary 45 open, 135 shift------------Even up with Nytro, turbo blows it away

3. Spring of my own design (exact details later)-------------------------------------------------------Viper blows away Nytro, and runs about one length slower than Turbo from stop to 50mph



Further testing and sharing of info with vendors before final details are released, can't have our two favorite Technical Wizards In Training telling me once again I don't know what I am talking about

Stringray, great thread. Is that your Vette? I had a 66 similar to your 67 and now have a 72 LT1 fully restored.
Back to snowmobiling. I have been reading the Viper threads as I might buy one some day. I currently have a 2011 Apex XTX and found that the Pink secondary spring actually binds and doesn't permit the Sheave to open all the way and let the belt drop down. I had a problem getting top end, but we have no snow now to test. I posted a thread on the Apex forum by blade072 about the secondary problem. I am not sure if the Viper's secondary is the same as the Apex or not. Some of the guys on the thread are adding a 4 mm spacer on the towers to allow more space for the spring. In addition to that, I machined the secondary to let it open more and removed some material in the spring area.
Jim

 

[stingray719]

Its lost in the clutch, the primary actually. After the 8DN debacle I went to work studying why this sled was so different from the Nytro clutches. I noticed our Viper came with a 2 stroke profile in the weight. That being a bump in the heel to raise take off revs (as 2 stroke have high horsepower not torque) and then a level ramp for about a third of the profile then a steeper ramp to raise rpm. And yes, why? This is a torque motor not a 2 stroke. I put the flat profile Nytro weights in (Matt from MPI suggested this, and this is what I did to our other boosted Yamahas so it wasn't anything new) and cut to desired rpm and that helped but it still seemed like something was missing. I mean this sled is a lot lighter than a Nytro and should be faster. So I came up with a bizarre test that worked.

All tests with flat profile 8FS weights cut down to 50 grams for above 10k altitude running. Weather about 25 degrees 3 inches snow on top of crust at 10k altitude. Race against 2008 Nytro with Can and a few add ons and a 2012 Nytro with 190hp Turbo


1. Stock clutches - Primary spring 35 open, 101 Shift -----------------------------------------------------Viper slightly slower than Nytro, Turbo blows it away

2. Stiffest primary spring made for this clutch (that I could find) Primary 45 open, 135 shift------------Even up with Nytro, turbo blows it away

3. Spring of my own design (exact details later)-------------------------------------------------------Viper blows away Nytro, and runs about one length slower than Turbo from stop to 50mph



Further testing and sharing of info with vendors before final details are released, can't have our two favorite Technical Wizards In Training telling me once again I don't know what I am talking about

Stringray, great thread. Is that your Vette? I had a 66 similar to your 67 and now have a 72 LT1 fully restored.
Back to snowmobiling. I have been reading the Viper threads as I might buy one some day. I currently have a 2011 Apex XTX and found that the Pink secondary spring actually binds and doesn't permit the Sheave to open all the way and let the belt drop down. I had a problem getting top end, but we have no snow now to test. I posted a thread on the Apex forum by blade072 about the secondary problem. I am not sure if the Viper's secondary is the same as the Apex or not. Some of the guys on the thread are adding a 4 mm spacer on the towers to allow more space for the spring. In addition to that, I machined the secondary to let it open more and removed some material in the spring area.
Jim

NOS-PRO who also has this special primary spring setup tried several different secondary springs with varying success and maybe he will reply here too. But the biggest issue I found was not enough pressure on the belt, solved by the fix mentioned above on the spring and weights. Now, if my fix works it means there is a problem elsewhere in this clutch and I honestly do not care enough to go farther finding the issue as I have a fix. No doubt somebody or some aftermarket company will find the actual "bug" in this setup.

Bill

 

[NOS-PRO]

Its lost in the clutch, the primary actually. After the 8DN debacle I went to work studying why this sled was so different from the Nytro clutches. I noticed our Viper came with a 2 stroke profile in the weight. That being a bump in the heel to raise take off revs (as 2 stroke have high horsepower not torque) and then a level ramp for about a third of the profile then a steeper ramp to raise rpm. And yes, why? This is a torque motor not a 2 stroke. I put the flat profile Nytro weights in (Matt from MPI suggested this, and this is what I did to our other boosted Yamahas so it wasn't anything new) and cut to desired rpm and that helped but it still seemed like something was missing. I mean this sled is a lot lighter than a Nytro and should be faster. So I came up with a bizarre test that worked.

All tests with flat profile 8FS weights cut down to 50 grams for above 10k altitude running. Weather about 25 degrees 3 inches snow on top of crust at 10k altitude. Race against 2008 Nytro with Can and a few add ons and a 2012 Nytro with 190hp Turbo


1. Stock clutches - Primary spring 35 open, 101 Shift -----------------------------------------------------Viper slightly slower than Nytro, Turbo blows it away

2. Stiffest primary spring made for this clutch (that I could find) Primary 45 open, 135 shift------------Even up with Nytro, turbo blows it away

3. Spring of my own design (exact details later)-------------------------------------------------------Viper blows away Nytro, and runs about one length slower than Turbo from stop to 50mph



Further testing and sharing of info with vendors before final details are released, can't have our two favorite Technical Wizards In Training telling me once again I don't know what I am talking about

Stringray, great thread. Is that your Vette? I had a 66 similar to your 67 and now have a 72 LT1 fully restored.
Back to snowmobiling. I have been reading the Viper threads as I might buy one some day. I currently have a 2011 Apex XTX and found that the Pink secondary spring actually binds and doesn't permit the Sheave to open all the way and let the belt drop down. I had a problem getting top end, but we have no snow now to test. I posted a thread on the Apex forum by blade072 about the secondary problem. I am not sure if the Viper's secondary is the same as the Apex or not. Some of the guys on the thread are adding a 4 mm spacer on the towers to allow more space for the spring. In addition to that, I machined the secondary to let it open more and removed some material in the spring area.
Jim

NOS-PRO who also has this special primary spring setup tried several different secondary springs with varying success and maybe he will reply here too. But the biggest issue I found was not enough pressure on the belt, solved by the fix mentioned above on the spring and weights. Now, if my fix works it means there is a problem elsewhere in this clutch and I honestly do not care enough to go farther finding the issue as I have a fix. No doubt somebody or some aftermarket company will find the actual "bug" in this setup.

Bill

Yes, I have tried the White, Green, Silver, black and kept going back to the pink. Setting softer will get you more mph so I am thinking machining the secondary or putting the washers under the helix will keep it from coil binding. But I did try wrapping the spring 6-2 (more spin/less mph) 6-1 (still spun/3 total more mph) 3-3 (better hook up/5 total more mph) 2-3 (slipped the belt on take off)

 

[shagman]

Its lost in the clutch, the primary actually. After the 8DN debacle I went to work studying why this sled was so different from the Nytro clutches. I noticed our Viper came with a 2 stroke profile in the weight. That being a bump in the heel to raise take off revs (as 2 stroke have high horsepower not torque) and then a level ramp for about a third of the profile then a steeper ramp to raise rpm. And yes, why? This is a torque motor not a 2 stroke. I put the flat profile Nytro weights in (Matt from MPI suggested this, and this is what I did to our other boosted Yamahas so it wasn't anything new) and cut to desired rpm and that helped but it still seemed like something was missing. I mean this sled is a lot lighter than a Nytro and should be faster. So I came up with a bizarre test that worked.

All tests with flat profile 8FS weights cut down to 50 grams for above 10k altitude running. Weather about 25 degrees 3 inches snow on top of crust at 10k altitude. Race against 2008 Nytro with Can and a few add ons and a 2012 Nytro with 190hp Turbo


1. Stock clutches - Primary spring 35 open, 101 Shift -----------------------------------------------------Viper slightly slower than Nytro, Turbo blows it away

2. Stiffest primary spring made for this clutch (that I could find) Primary 45 open, 135 shift------------Even up with Nytro, turbo blows it away

3. Spring of my own design (exact details later)-------------------------------------------------------Viper blows away Nytro, and runs about one length slower than Turbo from stop to 50mph



Further testing and sharing of info with vendors before final details are released, can't have our two favorite Technical Wizards In Training telling me once again I don't know what I am talking about

Stringray, great thread. Is that your Vette? I had a 66 similar to your 67 and now have a 72 LT1 fully restored.
Back to snowmobiling. I have been reading the Viper threads as I might buy one some day. I currently have a 2011 Apex XTX and found that the Pink secondary spring actually binds and doesn't permit the Sheave to open all the way and let the belt drop down. I had a problem getting top end, but we have no snow now to test. I posted a thread on the Apex forum by blade072 about the secondary problem. I am not sure if the Viper's secondary is the same as the Apex or not. Some of the guys on the thread are adding a 4 mm spacer on the towers to allow more space for the spring. In addition to that, I machined the secondary to let it open more and removed some material in the spring area.
Jim

NOS-PRO who also has this special primary spring setup tried several different secondary springs with varying success and maybe he will reply here too. But the biggest issue I found was not enough pressure on the belt, solved by the fix mentioned above on the spring and weights. Now, if my fix works it means there is a problem elsewhere in this clutch and I honestly do not care enough to go farther finding the issue as I have a fix. No doubt somebody or some aftermarket company will find the actual "bug" in this setup.

Bill

the problem of the coil bind has been around for years with we found it when we started racing the rx1. with the pink spring if you go above 3-3 it will bind there are several ways to fix. i have been working on the clutching with Nos and will be again tomorrow. please stay tuned. more info to come.

 

[YamahaTim]

Its lost in the clutch, the primary actually. After the 8DN debacle I went to work studying why this sled was so different from the Nytro clutches. I noticed our Viper came with a 2 stroke profile in the weight. That being a bump in the heel to raise take off revs (as 2 stroke have high horsepower not torque) and then a level ramp for about a third of the profile then a steeper ramp to raise rpm. And yes, why? This is a torque motor not a 2 stroke. I put the flat profile Nytro weights in (Matt from MPI suggested this, and this is what I did to our other boosted Yamahas so it wasn't anything new) and cut to desired rpm and that helped but it still seemed like something was missing. I mean this sled is a lot lighter than a Nytro and should be faster. So I came up with a bizarre test that worked.

All tests with flat profile 8FS weights cut down to 50 grams for above 10k altitude running. Weather about 25 degrees 3 inches snow on top of crust at 10k altitude. Race against 2008 Nytro with Can and a few add ons and a 2012 Nytro with 190hp Turbo


1. Stock clutches - Primary spring 35 open, 101 Shift -----------------------------------------------------Viper slightly slower than Nytro, Turbo blows it away

2. Stiffest primary spring made for this clutch (that I could find) Primary 45 open, 135 shift------------Even up with Nytro, turbo blows it away

3. Spring of my own design (exact details later)-------------------------------------------------------Viper blows away Nytro, and runs about one length slower than Turbo from stop to 50mph



Further testing and sharing of info with vendors before final details are released, can't have our two favorite Technical Wizards In Training telling me once again I don't know what I am talking about

Stringray, great thread. Is that your Vette? I had a 66 similar to your 67 and now have a 72 LT1 fully restored.
Back to snowmobiling. I have been reading the Viper threads as I might buy one some day. I currently have a 2011 Apex XTX and found that the Pink secondary spring actually binds and doesn't permit the Sheave to open all the way and let the belt drop down. I had a problem getting top end, but we have no snow now to test. I posted a thread on the Apex forum by blade072 about the secondary problem. I am not sure if the Viper's secondary is the same as the Apex or not. Some of the guys on the thread are adding a 4 mm spacer on the towers to allow more space for the spring. In addition to that, I machined the secondary to let it open more and removed some material in the spring area.
Jim

NOS-PRO who also has this special primary spring setup tried several different secondary springs with varying success and maybe he will reply here too. But the biggest issue I found was not enough pressure on the belt, solved by the fix mentioned above on the spring and weights. Now, if my fix works it means there is a problem elsewhere in this clutch and I honestly do not care enough to go farther finding the issue as I have a fix. No doubt somebody or some aftermarket company will find the actual "bug" in this setup.

Bill

the problem of the coil bind has been around for years with we found it when we started racing the rx1. with the pink spring if you go above 3-3 it will bind there are several ways to fix. i have been working on the clutching with Nos and will be again tomorrow. please stay tuned. more info to come.

It's great that you guys are testing! Good info!! I only wish I could test. I took her out today on a stretch today to do some testing and I just spin and dig up a ton of mud! Had to pressure wash it after that. It's funny cause I just pulled my truck over and unloaded. Didn't go to far, maybe 10 miles. Back and forth. Well I tried. With a bad set of thing come up I can't go out of town to ride.

 

[NOS-PRO]

Hey guys and gals!

Saturday, Shagman and I tried a bunch of things and wish he could have rode with me yesterday, but he had to leave. Trails Sunday were flat, groomed and set up which really made for different testing

Once again, pull apart, test, come back and pull apart and go test again.

Trails started out Saturday were very loose, lots of track spin and top speed was 94-95 as the trail was like a roller coaster with not washboard, but groomed ramps so to say and loose snow. Last week I was hitting the rev limiter so I thought I would try putting in a 3 gram rivot in the tip and try it, so I did. Shagman put a 3.7 in the middle and it didn't work, so I helped and we put in a 3.7 gram rivot in the tip also of his 8FP weights. I was a little low on rpm so I put a 3mm spacer in with my primary (previously was 2mm). Rpm's were a slight low at 8,650-8,720 but I wanted to wait for hardpack.

Our group of 5 drove 237 miles on Saturday and conditions went from loose snow to sticky, warm and slushy snow on the trails to mud on the logging roads with sound deep water puddles. Shagman and myself swapped sleds and his seemed to pull better on top end where mine was a monster on bottom end....but I was getting more mph on top which is weird...but none the less, 2 very quick sleds out of the hole. Andrew (my son on my Nytro) and I would line up and it was spin, spin, spin. The sleds were neck and neck after that, some me winning and some him winning. During our ride, we stopped to paly in the powder where both Shagman and myslef noticed the spring wrap on the secondary was too low and just sucked the belt down in the secondary. Was fun, but the deep snow was not as enjoyable with the belt slipping. Still, great fun and i got to see Shagman totally bury his sled on a hill....LMAO! When we arrived in Seney, I put on a new 8DN belt so I could break it in and try Saturday night and Sunday. The only great hook up I got was when Shagman dropped him arm and my XTX took off like a scared rabbit about 5 lengths in front of the Nytro. Tom (Mr Sled) took us on a road where I did back off and make a short run, I saw 106 but had a pucker moment when I saw everyone turning back onto the trail.

My setup now.... 8FP weights with a 3 gram rivot in the tip. G/W/G primary spring with a 3mm spacer, stock rollers. Secondary is Pink spring set at 6-1 with .080" washers under the helix which I kept the 45/39. 8DN belt
Rpm's were a max of 9,070

Shagman setup....8FP weights with a 3.7 rivot in the tip. 3mm spacer with a Y/G/Y spring, stock rollers. Secondary Pink spring set at 6-2 with washers under the 46/40 helix and 8DN belt.
Rpm's were a max of 9,150 where he said he was hitting the rev limiter.

Now, Sunday was a totally different situation as the warm weather and fresh grooming made trail 7 a slot car track. Skis in the air till 70 and hook like a mutha! Ran the smae setup but knocked it down to a wrap of 3-3 on the secondary. Better have 135 lbs. in that rear float as under power the skis are unless! Raced a few times and can say the Viper is back at it again with a maximum rpm of 8,940 - never hit the rev limiter and that oh so good freight train pull! Top speed on the trail was still just under 100 with the short runs I did and I know if there was a long enough path with hard crusted snow....107+ would be guaranteed. Talked to Allen Ulmer Friday and will be machining my clutches

The best part of this setup now is cruising speeds of 60 are at 6,700 rpm's which I am using a lot less fuel than the nytro. Back shift at 6-1 is very nice and it's a rocket from corner to corner with an awesome setup for 660 ft. snow drags. But, if you want top speed, the spring needs to be softened up as bottom end performance will give a little. My clutch mark is just a little better than it was last time, but I think the new belt....not the clutch setup helped with that. I think Allen is right with machining the primary to get better shift out.

None the less, it was great testing with you Shagman and wish the season wasn't over for me. Andrew enjoyed riding with you and says he is ready for springtime....lol

 

[shagman]

NOS-PRO

It was another great trip to Muni. Had lots of fun riding with you and Andrew. Need to do some finish work with the clutches, probably this weekend supposed to be cold at night here. i will be at our camp as we are going to start making syrup on Friday. Lots of time to test in the morning and during the day. will report findings. the Season is not done yet.

 

[stingray719]

I drove over 7 hours each way to South Dakota to go to the Yamaha demo and show them what I had done with the clutch setup. Like a true dumb@## I didn't consider going from 10k altitude to 6k and my Viper ran like crap on the rev limiter. I was truly embarrassed.

BUT, I got to ride the 2015 162 MTX with Turbo and MAN what a ride. The turbos ran so smooth the girlfriend changed her mind and now wants one....lol.

Catch the turbo demo if you can.

 

[NOS-PRO]

NOS-PRO

It was another great trip to Muni. Had lots of fun riding with you and Andrew. Need to do some finish work with the clutches, probably this weekend supposed to be cold at night here. i will be at our camp as we are going to start making syrup on Friday. Lots of time to test in the morning and during the day. will report findings. the Season is not done yet.

Was great riding with you also bud!

I'm going to send Andrew's info in to Yamaha! He's only 14 and the things he can do with a sled is just incredible in my eyes! Sunday he was playing more out in the powder...like he was just before we fueled up with gas on Saturday. He's a natural....what can I say? Best part is he tellls me if there is something wrong with the sled....poor handling, clutching not shifting right, belt slipping...he is spot on when there is a problem.

Let me know if you find a perfect balance between low end and top end. post results bud!

 

[NOS-PRO]

I drove over 7 hours each way to South Dakota to go to the Yamaha demo and show them what I had done with the clutch setup. Like a true dumb@## I didn't consider going from 10k altitude to 6k and my Viper ran like crap on the rev limiter. I was truly embarrassed.

BUT, I got to ride the 2015 162 MTX with Turbo and MAN what a ride. The turbos ran so smooth the girlfriend changed her mind and now wants one....lol.

Catch the turbo demo if you can.

That sucks Bill, too bad you couldn't have showed them how it really worked in your elevation.

Andrew and I were looking at the 162 MTX with turbo in the handout...man! That thing makes the XTX look like a shitzu next to a great dane!

 

[stingray719]

I drove over 7 hours each way to South Dakota to go to the Yamaha demo and show them what I had done with the clutch setup. Like a true dumb@## I didn't consider going from 10k altitude to 6k and my Viper ran like crap on the rev limiter. I was truly embarrassed.

BUT, I got to ride the 2015 162 MTX with Turbo and MAN what a ride. The turbos ran so smooth the girlfriend changed her mind and now wants one....lol.

Catch the turbo demo if you can.

That sucks Bill, too bad you couldn't have showed them how it really worked in your elevation.

Andrew and I were looking at the 162 MTX with turbo in the handout...man! That thing makes the XTX look like a shitzu next to a great dane!

With the 2.6 powerclaw it will take your breath away when the turbo spools. Has me thinking...................

 

[RTX]

Question for stingray and nos- pro
This weekend i tried to install a used 8dn belt
I could not get a new belt in time.
I tried shimming the secondary. I went all the way up to 4 shims on all 3 bolts and the belt still was not riding in the proper location. It was about 1/16 below the top of the clutch.
I decided against running like this and went back to 1 shim with the stock belt.
Now i see that nos pro has completely removed thi adjustment bolts from the secondary.
Is this why? Because it takes too many shims to get the belt where its supposed to be?
Also is this why they are machining the secondarys? To get the sheaves to close up more?
Should i just remove the bolts and run the 8dn belt

I have a green white green spring and a shim on the way.
Do you guys think i will see any improvement with just the spring?
I want to do the 8fp weights but have not ordered them yet because i am not clear in how you have them set up.
Are they empty with just i rivet in the tip?
Thanks

 

[stingray719]

Question for stingray and nos- pro
This weekend i tried to install a used 8dn belt
I could not get a new belt in time.
I tried shimming the secondary. I went all the way up to 4 shims on all 3 bolts and the belt still was not riding in the proper location. It was about 1/16 below the top of the clutch.
I decided against running like this and went back to 1 shim with the stock belt.
Now i see that nos pro has completely removed thi adjustment bolts from the secondary.
Is this why? Because it takes too many shims to get the belt where its supposed to be?
Also is this why they are machining the secondarys? To get the sheaves to close up more?
Should i just remove the bolts and run the 8dn belt

I have a green white green spring and a shim on the way.
Do you guys think i will see any improvement with just the spring?
I want to do the 8fp weights but have not ordered them yet because i am not clear in how you have them set up.
Are they empty with just i rivet in the tip?
Thanks

I added two washer from the hardware store to each bolt, so I am not sure how that equates to Yamaha shims but those two washers added alot compared to the stock ones. But yes, you need a little of the belt above the sheave on mine it is just the ribs above. I would buy a new 8DN belt they are half the price of a 8JP.

Green-white-green alone will help but the big change comes when you add the shim. NOS-PRO has actually went to 3mm shim but I will let him explain what he did. By all means get the 8FP weights and try them, if you rev over 8800 put a 3gram rivet in the end of the weight and once again NOS-PRO did that testing. I used 8FS weight cut down for altitude.

 

[shagman]

Question for stingray and nos- pro
This weekend i tried to install a used 8dn belt
I could not get a new belt in time.
I tried shimming the secondary. I went all the way up to 4 shims on all 3 bolts and the belt still was not riding in the proper location. It was about 1/16 below the top of the clutch.
I decided against running like this and went back to 1 shim with the stock belt.
Now i see that nos pro has completely removed thi adjustment bolts from the secondary.
Is this why? Because it takes too many shims to get the belt where its supposed to be?
Also is this why they are machining the secondarys? To get the sheaves to close up more?
Should i just remove the bolts and run the 8dn belt

I have a green white green spring and a shim on the way.
Do you guys think i will see any improvement with just the spring?
I want to do the 8fp weights but have not ordered them yet because i am not clear in how you have them set up.
Are they empty with just i rivet in the tip?
Thanks

If you add more than 2 shims to the secondary the bolts don't touch any more. so you can just take them out. with a new 8dn and the bolts out the belt will sit about 3/16" above the side of secondary. also you need 3 1mm shims in the primary with that spring. secondary was also shimed on the tower bolts under the helix to prevent coil bind. .090" washer with flat ground on one side to clear helix.