Nytro belt issues please help

justinkredible56 · Jan 3, 2011

Well I've gotten about 1300 miles on my sled so far and love it wouldn't trade it for any other sled and I've ridden all of the other brands. That being said I'm having a big issue with it right now. I'm burning belts like it's going out of style! I've got the hartman custom clutch setup on it right now but the issue happened when the clutching was stock also. My rpms are in check and I'm using the yamaha belts. I've gone through about 4 belts so far this season trying to resolve the issue but have yet to do so. I believe my belt deflection is in check but have not checked my center to center alignment but didn't figure it was an issue. The belt threads are coming undone on the belts every time. I have put screen around every vent and opening to prevent snow from entering and it seemed to help a little bit. I wash my belts in the dish washer every time. I clean my clutches every time I blow a belt. I believe I break in my belts correctly but I still have no idea why I keep blowing them. My clutches are very hot every time I check them on the hill which is the obvious reason the belt threads come out. My question is how do I fix this? I've played with my secondary spring pre tension but it seemed to have no effect.
Thanks in advance,
-Justin

twincam88 · Jan 4, 2011

i would really check your clutch alignment. that will eat belts like crazy. also scuff the sheaves of both clutch's with scotch brite working from out side straight to the center. it takes the glaze off them. you can do this whenever its in the shop(every couple rides)

justinkredible56 · Jan 4, 2011

twincam88 said:
i would really check your clutch alignment. that will eat belts like crazy. also scuff the sheaves of both clutch's with scotch brite working from out side straight to the center. it takes the glaze off them. you can do this whenever its in the shop(every couple rides)

I will get both of those things done today, thanks for the advice...that would explain it burning belts with both stock and custom clutching. Any other ideas?

Shermanator · Jan 4, 2011

For what its worth, I tried a different secondary spring from the stock "pink" one, the new one having more tension. My rollers in the primary were stock. I did a ride and a half and the belt exploded and the clutches were so hot I coudn't even touch them. Problem was, not "matching" the primary's tension with different rollers to the new secondary's springs increased tension, caused the belt to slip and heat up, big time. And not slip so you could smell it burning, just slipping that it created more friction and blew! Put the stock secondary spring back in and 500 km later she's running cool! Sherm

justinkredible56 · Jan 5, 2011

Figured I would update this thread. I have spoken with Tom Hartman several times about this issue and he is dead set on the problem being that snow is getting into my clutch compartment/area. I told him all that I have done as far as screening/taping things off and he insists it's snow and/or steam getting in there.

So...I used up half a roll of duct tape and more screen door material and now have every opening you can imagine up to and including foot saddle aluminum holes. The entire bottom plastic that runs from the top of the shock tower to the bottom of the running boards is duct taped to the maximum. I already had a lot of it duct taped but now all of it is. The only thing left to do to prevent snow getting in after this will be one of those complete clutch covers that the water racers use.

Next I used some fine grit emery cloth and went over my clutches to remove any glaze that may have accrued on them over the past belt blow up. I have cleaned my clutches with brake cleaner after every blown belt but have never felt the need for emery cloth. After scrubbing them with emery cloth I went back over them with a heavy duty scotch-brite scour pad. Finishing the job with brake cleaner and paper towels. I scrubbed the brand new belt that had already gone through the dish washer with warm water and soap and then gently scrubbed it with scotch-brite as well.

The clutch alignment is within spec according to the local Yamaha shop. I had them confirm that today.

Hopefully after all of this I will at least see more than 150 miles on a belt....I'm crossing my fingers. My question is why do I have to go through all of this hassle? Why is every other nytro with the wide open vents and non-sealed clutch compartment able to get over 1.5k miles on one belt?!?!

Any and every comment is welcome!

-Justin

0007 · Jan 5, 2011

I think you need a second opinion, you've got to have someone ride the sled and see what happens
Is it possible you put the helix on wrong?

Climbmax · Jan 5, 2011

Unless you are a large individual or pulling a trailer......you have a setting problem . Stock set ups will go a year on a belt. If your clutches are hot your slipping a belt. You will know when its due to snow ingenstion....it kinda chuggs or feels like something is in your clutch.
Like 0007 says........a second opinion is required.
Safe sleddin

RS

summitboy · Jan 6, 2011

I think u should breakdown your clutching setup in detail and you will get a setup that will get you way closer than what you are. Detail is the key ! Fill in the following:

Sled
Track-
Turbo kit-

Primary
Spring-
Weights-type and weight
Rollers-

Secondary
Spring-type/color wound to what degree #/#
Helix-degree

Gearing
Top-
Bottom-

Your setup will be within inches of everyone elses setup running the same boost and hp as your sled. Don't forget everyone has the magic potion ! The trick is to fine tune it for your riding style, track, and hp. Some guys ride chutes, some guys sit around, some guys boondock, some guys are just plain breakers. Pick your poison and some slight changes will get you close.

Cheers

SB

twincam88 · Jan 6, 2011

also remember the belts have to be "broken in" ride easy on it for around 60 miles. no WOT runs. i get my old man to break belts in for me. he goes out and putts around on his xtx and loves it mean while i am at home laughing cause i dont have to do it. they just dont last if you dont break them in. its gay

justinkredible56 · Jan 6, 2011

Sled----09 Nytro
Track- 162 Attack 20 in hillclimb position
Turbo kit- it's N/A but it does have a full AAEN exhaust that is supposed to put me at 157 and I would have to say it feels awfully close to that.

Primary
Spring- Yellow Pink Yellow
Weights-8dn-10 yamaha weights with (2) 4.5 gram rivets in them = 48.76grams per weight
Rollers- 14.5 rollers.

Secondary
Spring-Yamaha Black spring with Silver mark currently wound to 100* but has been at every setting between 60-100.
Helix-starts at 39* and then ends at 36*

Gearing
Top- 19T
Bottom- 40T

I am a large individual I guess. The clutching was set to accommodate that. I weigh probably 310 with my backpack and gear on. If it has snow on it that's what I ride (tree riding, hillclimbing, and boondocking)so it is a lot of WOT riding. Don't get it wrong I may be big but I'm in VERY good shape.

justinkredible56 · Jan 6, 2011

0007 said:
I think you need a second opinion, you've got to have someone ride the sled and see what happens
Is it possible you put the helix on wrong?

I'm 100% sure the helix is on correctly. There is really only one way to put it on with this specific helix. If your talking about pre-tension on the secondary spring it is set to the specifications Hartman Inc. wanted, which is 70*. I have been playing with that pre-tension though and it is currently set at 100*.

bigbird · Jan 6, 2011

justinkredible56 said:
Sled----09 Nytro
Track- 162 Attack 20 in hillclimb position
Turbo kit- it's N/A but it does have a full AAEN exhaust that is supposed to put me at 157 and I would have to say it feels awfully close to that.

Primary
Spring- Yellow Pink Yellow
Weights-8dn-10 yamaha weights with (2) 4.5 gram rivets in them = 48.76grams per weight
Rollers- 14.5 rollers.

Secondary
Spring-Yamaha Black spring with Silver mark currently wound to 100* but has been at every setting between 60-100.
Helix-starts at 39* and then ends at 36*

Gearing
Top- 19T
Bottom- 40T

I am a large individual I guess. The clutching was set to accommodate that. I weigh probably 310 with my backpack and gear on. If it has snow on it that's what I ride (tree riding, hillclimbing, and boondocking)so it is a lot of WOT riding. Don't get it wrong I may be big but I'm in VERY good shape.

I weigh similar to you, run 18-20 lbs. boost and have a 174 track. used one belt last in 2000kms of mountain riding. it is definately your setup/alignment. these sleds typically do not eat belts, even on boost.

justinkredible56 · Jan 6, 2011

Also I wanted to mention that my track speed seems very low...down around 32-33mph. From what I have gathered/seen with other nytro's that's pretty low and I'm fairly sure both of these problems go hand in hand.

4strokeperformance · Jan 6, 2011

nytro belts

Im not as big as you but I run 18 42 gearing 162 ce. Plenty fast and after a long pull I can grab the belt and not get burned. Good luck.

justinkredible56 · Jan 7, 2011

justinkredible56 · Jan 10, 2011

Anyone have any ideas at all?

Canoehead · Jan 11, 2011

Hopefully this isn't a dumb question but, are you installing the belts in the proper rotational direction?

twincam88 · Jan 11, 2011

Canoehead said:
Hopefully this isn't a dumb question but, are you installing the belts in the proper rotational direction?

i almost forgot to ask him about this good one!!!

justinkredible56 · Jan 11, 2011

Canoehead said:
Hopefully this isn't a dumb question but, are you installing the belts in the proper rotational direction?

Haha I appreciate the attempt to be thorough, and yes I do install them in the correct rotational direction.

LOKI · Jan 11, 2011

you need to address your gearing. With your weight & 162 track & high elevation, a change out of the top gear to an 18t should make alot of difference in clutch heat. You may also be able to back off you secondary spring degrees with the change in gearing.

Hope this helps.

Nytro belt issues please help

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