Trying The 8DN BELT

[stingray719]

Well heard back from my dealer on my over reving , Yamaha told them verify belt deflection, track tension and if those check out its probably normal. They said the gauges can vary a couple hundred rpm. Pretty disappointed with Yamaha on that answer. So I guess hitting the Rev limiter is normal. Bet if it screwed up my engine they would tell me I shouldn't let it do that and to go fly a kite on that as well. Have a call in to Ulmer racing, waiting for a reply.

If you have the 8DN on and still over revving you can do what is not the best solution but acceptable. Decrease spring pressure on the secondary and you can get 200 to 300 rpm easy. Also increases upshift rate which may also help you. Here in the high country I wind our secondaries tight to cause slow upshift and quick backshift at the cost of top speed because we don't care about top speed in the trees.

Just grab your favorite 10mm socket and rachet and take the 3 helix nuts off. Set spring one or two less than now and put helix back on....easy! Oh yeah taking belt off first is wise.....lol. Quick and easy free test!



Secondary numbers add to angle, 6 on helix and 1 on secondary = 70. 3 on helix and 1 on secondary = 40...etc. I suspect yours might be on 70 (6+1).

Let us know if you tried it and if it solved your problem!

Stingray - Are you running a cat clutch with the 10mm nuts? Cause my nuts are 12mm

Just giving ya crap bud!

Good info and I would agree with stingray on the "change" to your stock components.....it's free, just have to get your hands dirty

OOPS! It is the primary clutch are 10mm...I will go edit the other post. Thanks!

 

[DeerHuntr]

Talked with Ulmer today, he told me to try a new belt first but if that doesn't do it he told me to do exactly what you did stingray. Told me it's worth a shot. He also told me the stock weights are pretty much loaded from the factory except for the tip and that's not what I really need so it's pretty limited what I can do. Had a good talk with him, honestly really impressed that he took the time to help given I haven't bought anything from him. He also said he is working on a setup for the 8dn, he thinks that there is some gains to make with it. Going out to tinker with it in the morning.

 

[YamahaTim]

Talked with Ulmer today, he told me to try a new belt first but if that doesn't do it he told me to do exactly what you did stingray. Told me it's worth a shot. He also told me the stock weights are pretty much loaded from the factory except for the tip and that's not what I really need so it's pretty limited what I can do. Had a good talk with him, honestly really impressed that he took the time to help given I haven't bought anything from him. He also said he is working on a setup for the 8dn, he thinks that there is some gains to make with it. Going out to tinker with it in the morning.

Yep, that's what I'm going to get. He is a great guy. So I'm cool with buying something from someone that will take the time to help even though you didn't buy anything! So I'm sold!!

 

[stingray719]

Talked with Ulmer today, he told me to try a new belt first but if that doesn't do it he told me to do exactly what you did stingray. Told me it's worth a shot. He also told me the stock weights are pretty much loaded from the factory except for the tip and that's not what I really need so it's pretty limited what I can do. Had a good talk with him, honestly really impressed that he took the time to help given I haven't bought anything from him. He also said he is working on a setup for the 8dn, he thinks that there is some gains to make with it. Going out to tinker with it in the morning.

Don't let that get out, people might quit saying to me "you don't have a clue"

BTW 8FS weights are 5 grams heavier than stock Viper weights and are a flat profile, came on mountain Nytros and others mountain yamahas. I put them on mine and actually have too much weight now. But really I think a new 8DN belt and unwinding your secondary will do it.

 

[DeerHuntr]

Talked with Ulmer today, he told me to try a new belt first but if that doesn't do it he told me to do exactly what you did stingray. Told me it's worth a shot. He also told me the stock weights are pretty much loaded from the factory except for the tip and that's not what I really need so it's pretty limited what I can do. Had a good talk with him, honestly really impressed that he took the time to help given I haven't bought anything from him. He also said he is working on a setup for the 8dn, he thinks that there is some gains to make with it. Going out to tinker with it in the morning.

Yep, that's what I'm going to get. He is a great guy. So I'm cool with buying something from someone that will take the time to help even though you didn't buy anything! So I'm sold!!

Exactly, he sold a clutch kit today and maybe some other stuff and doesn't even know it yet. Really impressed he took the time to call me back and discuss this with me without really even pushing his product to be honest. Speaks volumes about the guy.

 

[YamahaTim]

Same here, talked with me for around a hour. And never tried to sell anything. But now im getting the set he has for the turbo. And 8DN.

 

[kritter5150]

Here is a picture of how high the 8DN sits in the secondary. This so you guys can go off of. now on the back side of the secondary there should already be one washer there. you will just need to add that exact same washer to it and thats what i did to shim it for the 8DN belt. the picture should show the deflection. i have over 500 miles on the belt now and no issues. i can beat the crap out of it jump off the sled rip off the side panel and put my hands on the clutch and its not that hot. where as my stock belt was super hot! hope this helps everyone.

made the switch to the 8dn belt today for my turbo viper. rpms seemed more consistent. clutches cooler. less belt dust. less slipping. then changed my helix to a dalton components 38/44. running at holes 2and 6. finally reaching 8900-9000 rpms. was only hitting 8300-8400 before. thing pulls alot harder. going to ride some trails this weekend. so it ll be good test. i have the mcx 190 kit. with the optional mcx clutch weight kit. after having it dynoed by dynotech industries in new york. jim at dynotech was very impressed with the quietness and the efi box. if anyone knows his #*$&@ about snowmobile engines. its him. extremely happywith the viper. and this turbo kit. finally getting the clutching dialed in will be a huge relief!!

 

[kritter5150]

Here is a picture of how high the 8DN sits in the secondary. This so you guys can go off of. now on the back side of the secondary there should already be one washer there. you will just need to add that exact same washer to it and thats what i did to shim it for the 8DN belt. the picture should show the deflection. i have over 500 miles on the belt now and no issues. i can beat the crap out of it jump off the sled rip off the side panel and put my hands on the clutch and its not that hot. where as my stock belt was super hot! hope this helps everyone.

made the switch to the 8dn belt today for my turbo viper. rpms seemed more consistent. clutches cooler. less belt dust. less slipping. then changed my helix to a dalton components 38/44. running at holes 2and 6. finally reaching 8900-9000 rpms. was only hitting 8300-8400 before. thing pulls alot harder. going to ride some trails this weekend. so it ll be good test. i have the mcx 190 kit. with the optional mcx clutch weight kit. after having it dynoed by dynotech industries in new york. jim at dynotech was very impressed with the quietness and the efi box. if anyone knows his poop about snowmobile engines. its him. extremely happywith the viper. and this turbo kit. finally getting the clutching dialed in will be a huge relief!!

btw. i did not type poop

 

[YamahaTim]

Here is a picture of how high the 8DN sits in the secondary. This so you guys can go off of. now on the back side of the secondary there should already be one washer there. you will just need to add that exact same washer to it and thats what i did to shim it for the 8DN belt. the picture should show the deflection. i have over 500 miles on the belt now and no issues. i can beat the crap out of it jump off the sled rip off the side panel and put my hands on the clutch and its not that hot. where as my stock belt was super hot! hope this helps everyone.

made the switch to the 8dn belt today for my turbo viper. rpms seemed more consistent. clutches cooler. less belt dust. less slipping. then changed my helix to a dalton components 38/44. running at holes 2and 6. finally reaching 8900-9000 rpms. was only hitting 8300-8400 before. thing pulls alot harder. going to ride some trails this weekend. so it ll be good test. i have the mcx 190 kit. with the optional mcx clutch weight kit. after having it dynoed by dynotech industries in new york. jim at dynotech was very impressed with the quietness and the efi box. if anyone knows his poop about snowmobile engines. its him. extremely happywith the viper. and this turbo kit. finally getting the clutching dialed in will be a huge relief!!

btw. i did not type poop

Lol

 

[RTX Meirda]

Here is a picture of how high the 8DN sits in the secondary. This so you guys can go off of. now on the back side of the secondary there should already be one washer there. you will just need to add that exact same washer to it and thats what i did to shim it for the 8DN belt. the picture should show the deflection. i have over 500 miles on the belt now and no issues. i can beat the crap out of it jump off the sled rip off the side panel and put my hands on the clutch and its not that hot. where as my stock belt was super hot! hope this helps everyone.

made the switch to the 8dn belt today for my turbo viper. rpms seemed more consistent. clutches cooler. less belt dust. less slipping. then changed my helix to a dalton components 38/44. running at holes 2and 6. finally reaching 8900-9000 rpms. was only hitting 8300-8400 before. thing pulls alot harder. going to ride some trails this weekend. so it ll be good test. i have the mcx 190 kit. with the optional mcx clutch weight kit. after having it dynoed by dynotech industries in new york. jim at dynotech was very impressed with the quietness and the efi box. if anyone knows his poop about snowmobile engines. its him. extremely happywith the viper. and this turbo kit. finally getting the clutching dialed in will be a huge relief!!

Did you use a brand new 8dn belt or used? Also did you use the washers to adjust ride height?

 

[YamahaTim]

Here is a picture of how high the 8DN sits in the secondary. This so you guys can go off of. now on the back side of the secondary there should already be one washer there. you will just need to add that exact same washer to it and thats what i did to shim it for the 8DN belt. the picture should show the deflection. i have over 500 miles on the belt now and no issues. i can beat the crap out of it jump off the sled rip off the side panel and put my hands on the clutch and its not that hot. where as my stock belt was super hot! hope this helps everyone.

made the switch to the 8dn belt today for my turbo viper. rpms seemed more consistent. clutches cooler. less belt dust. less slipping. then changed my helix to a dalton components 38/44. running at holes 2and 6. finally reaching 8900-9000 rpms. was only hitting 8300-8400 before. thing pulls alot harder. going to ride some trails this weekend. so it ll be good test. i have the mcx 190 kit. with the optional mcx clutch weight kit. after having it dynoed by dynotech industries in new york. jim at dynotech was very impressed with the quietness and the efi box. if anyone knows his poop about snowmobile engines. its him. extremely


happywith the viper. and this turbo kit. finally getting the clutching dialed in will be a huge relief!!

Did you use a brand new 8dn belt or used? Also did you use the washers to adjust ride height?

Yes they put a brand new belt in it and, and they added one more of the same washer that was already in there. So two total.

 

[RTX Meirda]

Here is a picture of how high the 8DN sits in the secondary. This so you guys can go off of. now on the back side of the secondary there should already be one washer there. you will just need to add that exact same washer to it and thats what i did to shim it for the 8DN belt. the picture should show the deflection. i have over 500 miles on the belt now and no issues. i can beat the crap out of it jump off the sled rip off the side panel and put my hands on the clutch and its not that hot. where as my stock belt was super hot! hope this helps everyone.

made the switch to the 8dn belt today for my turbo viper. rpms seemed more consistent. clutches cooler. less belt dust. less slipping. then changed my helix to a dalton components 38/44. running at holes 2and 6. finally reaching 8900-9000 rpms. was only hitting 8300-8400 before. thing pulls alot harder. going to ride some trails this weekend. so it ll be good test. i have the mcx 190 kit. with the optional mcx clutch weight kit. after having it dynoed by dynotech industries in new york. jim at dynotech was very impressed with the quietness and the efi box. if anyone knows his poop about snowmobile engines. its him. extremely happywith the viper. and this turbo kit. finally getting the clutching dialed in will be a huge relief!!

Did you use a brand new 8dn belt or used? Also did you use the washers to adjust ride height?

 

[YamahaTim]

Lol..yes and yes

 

[kritter5150]

Here is a picture of how high the 8DN sits in the secondary. This so you guys can go off of. now on the back side of the secondary there should already be one washer there. you will just need to add that exact same washer to it and thats what i did to shim it for the 8DN belt. the picture should show the deflection. i have over 500 miles on the belt now and no issues. i can beat the crap out of it jump off the sled rip off the side panel and put my hands on the clutch and its not that hot. where as my stock belt was super hot! hope this helps everyone.

made the switch to the 8dn belt today for my turbo viper. rpms seemed more consistent. clutches cooler. less belt dust. less slipping. then changed my helix to a dalton components 38/44. running at holes 2and 6. finally reaching 8900-9000 rpms. was only hitting 8300-8400 before. thing pulls alot harder. going to ride some trails this weekend. so it ll be good test. i have the mcx 190 kit. with the optional mcx clutch weight kit. after having it dynoed by dynotech industries in new york. jim at dynotech was very impressed with the quietness and the efi box. if anyone knows his poop about snowmobile engines. its him. extremely happywith the viper. and this turbo kit. finally getting the clutching dialed in will be a huge relief!!

Did you use a brand new 8dn belt or used? Also did you use the washers to adjust ride height?

slightly used. maybe 25 miles on it and yes i put the washers on the back of the secondary

 

[YamahaTim]

Here is a picture of how high the 8DN sits in the secondary. This so you guys can go off of. now on the back side of the secondary there should already be one washer there. you will just need to add that exact same washer to it and thats what i did to shim it for the 8DN belt. the picture should show the deflection. i have over 500 miles on the belt now and no issues. i can beat the crap out of it jump off the sled rip off the side panel and put my hands on the clutch and its not that hot. where as my stock belt was super hot! hope this helps everyone.

made the switch to the 8dn belt today for my turbo viper. rpms seemed more consistent. clutches cooler. less belt dust. less slipping. then changed my helix to a dalton components 38/44. running at holes 2and 6. finally reaching 8900-9000 rpms. was only hitting 8300-8400 before. thing pulls alot harder. going to ride some trails this weekend. so it ll be good test. i have the mcx 190 kit. with the optional mcx clutch weight kit. after having it dynoed by dynotech industries in new york. jim at dynotech was very impressed with the quietness and the efi box. if anyone knows his poop about snowmobile engines. its him. extremely happywith the viper. and this turbo kit. finally getting the clutching dialed in will be a huge relief!!

Did you use a brand new 8dn belt or used? Also did you use the washers to adjust ride height?

slightly used. maybe 25 miles on it and yes i put the washers on the back of the secondary

25 miles is pretty much new with a little break in. Sounds good to me! Give it a shot!