RT Ryder
Newbie
I am having huge belt issues on a 2008 Nytro with a 270 MCX turbo kit. I just bought the machine and have gone through 5 belts in 250km. Every time the belt blows, it leaves a hard rub patch on the bottom inside of the secondary and some light scuffs on the top of the primary.
I blew 2 in one day, so I took the secondary apart to see if there was anything broken or worn out and couldn't see anything wrong. I cleaned it up and put it all back together and took the sled for another ride. I blew the 3rd belt, then changed the helix from a 45 to a 47, twisted the epi purple secondary spring almost a full turn (was on 3 on the helix and I can't read the numbers on the secondary sheave) because I thought it was slipping real bad in the secondary causing it to explode. This didn't help.
On wide open throttle, it blew the belt again with 7 km. I finally got a straight bar (clutch alignment tool for an old vmax)and found out that the primary was sucked in towards the secondary. This made perfect sense to me that when the primary closes, eventually the belt grabs on the top of the clutch and spins the belt in the secondary until it explodes. After moving the alignment about 1/4", twisting the front of the end of the engine clockwise, I finally was aligned. I also changed the secondary spring to a cat green and twisted it about 1/3 to 1/2 a turn.
I thought this would be my solution but last weekend I blew the 5th belt. Measured the center to center (very poorly) by going from the center of the primary bolt to the center of the secondary bolt and it measured 27 cm. I compared this to a couple friends nytros and they were the same.
My RPMs are good, ranging from 8700 to 8900 depending on the snow conditions. I believe 8bu weights in the primary and cant remember the spring color, but a friend said my primary is set up perfect for 12lbs
I am out of thoughts on how to solve this. Any opinions?
I blew 2 in one day, so I took the secondary apart to see if there was anything broken or worn out and couldn't see anything wrong. I cleaned it up and put it all back together and took the sled for another ride. I blew the 3rd belt, then changed the helix from a 45 to a 47, twisted the epi purple secondary spring almost a full turn (was on 3 on the helix and I can't read the numbers on the secondary sheave) because I thought it was slipping real bad in the secondary causing it to explode. This didn't help.
On wide open throttle, it blew the belt again with 7 km. I finally got a straight bar (clutch alignment tool for an old vmax)and found out that the primary was sucked in towards the secondary. This made perfect sense to me that when the primary closes, eventually the belt grabs on the top of the clutch and spins the belt in the secondary until it explodes. After moving the alignment about 1/4", twisting the front of the end of the engine clockwise, I finally was aligned. I also changed the secondary spring to a cat green and twisted it about 1/3 to 1/2 a turn.
I thought this would be my solution but last weekend I blew the 5th belt. Measured the center to center (very poorly) by going from the center of the primary bolt to the center of the secondary bolt and it measured 27 cm. I compared this to a couple friends nytros and they were the same.
My RPMs are good, ranging from 8700 to 8900 depending on the snow conditions. I believe 8bu weights in the primary and cant remember the spring color, but a friend said my primary is set up perfect for 12lbs
I am out of thoughts on how to solve this. Any opinions?
JP270NYTRO
Pro
check the bottom of your secondary, the yami belts are really hard and the 270kit will gear the nytro out and keep spinning the belt in the secondary! it will wear grooves in the bottom of the secondary and in some cases wear through the sheaves on the bottom of the secondary witch will cord the belt and blow it!
rxrider
Jan-Ove Pedersen
- Joined
- Apr 25, 2003
- Messages
- 7,355
- Reaction score
- 64
- Points
- 1,753
- Location
- Lakselv - 70N & 25E
- Country
- Norway
- Snowmobile
- 2014 Phazer XTX, 2013 Phazer RTX, 2008 Apex RTX, 2007 Warrior, 2006 Attak
RT Ryder - welcome to the site. Please add Your location to Your user profile, site requirement.
The 47 helix will even make it worse.
You need a shallower end angle to make more pressure on the belt in the secondary.
I recommend a 51/43 helix.
Also measure off-set between the primary and secondary. Should be set at 15 mm.
Use a straight edge on the inside of the primary and measure the alignment on the front and rear of the secondary. You shold get the same number both front and rear, if not Your engine is out of alignment. This measurement and the off-set is the two important measurements to keep in check.
I do not care much about the center to center measurement as it won't tell you anything about what's importent; alignment and off-set aka engine/secondary shaft parallellity.
rxrider
TY Management Team
The 47 helix will even make it worse.
You need a shallower end angle to make more pressure on the belt in the secondary.
I recommend a 51/43 helix.
Also measure off-set between the primary and secondary. Should be set at 15 mm.
Use a straight edge on the inside of the primary and measure the alignment on the front and rear of the secondary. You shold get the same number both front and rear, if not Your engine is out of alignment. This measurement and the off-set is the two important measurements to keep in check.
I do not care much about the center to center measurement as it won't tell you anything about what's importent; alignment and off-set aka engine/secondary shaft parallellity.
rxrider
TY Management Team
Vectorboost
Extreme
- Joined
- Jan 16, 2014
- Messages
- 72
- Reaction score
- 2
- Points
- 208
- Location
- Saratoga, Minnesota
- Country
- USA
- Snowmobile
- 06 vector mcx turbo
Was your sled blowing belts consistently at the same speed. I was blowing belts last year on my mcx vector every time at a speedo reading of 110. i had re-geared sled the previous year to lower gears. Didnt work once i added turbo. found out my sled was undergeared for the power, driving belt over the primary. and boooom.. geared sled taller this year and no problems.
RT Ryder
Newbie
Thanks for the replies. I have heard about the belts wearing out the secondary and checked the sheaves and they look smooth, no wearing.
I will get a flat bar and measure the alignment again and also measure the offset. As for the helix, I will try to track down a 51/43 but I believe that the issue is more than whats in the clutch. I was thinking about the gearing as well but haven't checked it yet. I will have lots of time to look at this now since all our snow melted last week.
Keep the ideas coming guys, I really appreciate it.
I will get a flat bar and measure the alignment again and also measure the offset. As for the helix, I will try to track down a 51/43 but I believe that the issue is more than whats in the clutch. I was thinking about the gearing as well but haven't checked it yet. I will have lots of time to look at this now since all our snow melted last week.
Keep the ideas coming guys, I really appreciate it.
