Nytro belt issues please help

acutah · Jan 20, 2011

Maybe I am crazy but I have never payed any attention to breaking in a belt. I wash it and bent it around, throw her on and give'r hell. I haven't ever blown a belt in my life. My feeling is that you are now a bit paranoid about the whole thing. I feel for ya bro. I've been there on jetting my sled in the past. Let me know if you ever decide to go with the 18t.

Linc · Jan 20, 2011

Don't be afraid to lower the weight in the ramps, that's why they are designed that way, a rule of thumb is about 200 rpm per 1 gram of weight. Don't forget, you'll lose 3% of air density for every 1000 ft of elevation gain, so 3% of power loss for every 1000 ft of elevation, so over rev down low to get where you want to be at your riding elev.

summitboy · Jan 20, 2011

Sounds good. I would like to know the weight of your 8FS. You will get a little closer once you put the B-W-B spring. I would scotchbrite the sheaves and go for a good run and re post the pics.

Once you get the Daltons you most likely will go down in weight a little due to the profile. I bet you will be around the 65 gram range with the Daltons.

Stop and feel clutch heat as well.

I too don't break belts in. Put em on and abuse them ! 45 bucks US is cheap !

justinkredible56 · Jan 21, 2011

acutah said:
Maybe I am crazy but I have never payed any attention to breaking in a belt. I wash it and bent it around, throw her on and give'r hell. I haven't ever blown a belt in my life. My feeling is that you are now a bit paranoid about the whole thing. I feel for ya bro. I've been there on jetting my sled in the past. Let me know if you ever decide to go with the 18t.

I've owned 5 sleds since I was 15 and never broke in a belt, let alone wash it before use. I just slapped a new one on and never thought twice about it. After I burned up the first 2 belts on my nytro I decided I needed to do something different because there was obviously a problem. Since then I've been breaking in the belts a minimum of 15 miles a piece and always run scotch brite over the clutches and run my belt through the dishwasher before the new belt is put on. In my eyes is hella over kill but if it will give me an extra 50 miles on a belt I'll keep with it!

Check your PM about the 18t sprocket.

justinkredible56 · Jan 21, 2011

summitboy said:
Sounds good. I would like to know the weight of your 8FS. You will get a little closer once you put the B-W-B spring. I would scotchbrite the sheaves and go for a good run and re post the pics.

Once you get the Daltons you most likely will go down in weight a little due to the profile. I bet you will be around the 65 gram range with the Daltons.

Stop and feel clutch heat as well.

I too don't break belts in. Put em on and abuse them ! 45 bucks US is cheap !

I have 55 miles on this belt so far. I'll buy a digital scale tomorrow and post the weights of the 8FS's and pics of the clutches.

Right before I headed back to the truck I gave the belt hell and looked for heat/trackspeed/RPM.
Heat: After about 5-6 back to back pulls on a steep hill with VERY setup snow (6 inches of fluff on top of cement base), I checked the clutches and they were warm at the top of the sheaves, and hot but didn't burn my fingers at the base of the sheaves. Before the clutching changes I could spit on them and it would instantly boil. The primary and secondary feel close to the same temp to the touch.

Trackspeed: In these snow conditions the trackspeed isn't very relevant because I want deep powder performance and this was anything but that. Perfect snow conditions to break in a belt though. Pulling a steep slope in fresh tracks I was seeing 38-40 mph.

RPM: Right now I'm taching the same on flat ground as I am on a steep pull and that's right around 8000-8300. Still off base but I'm waiting for my primary spring to adjust my weights.

Still using the 14.5 rollers right now. When we get some better snow conditions and I have my other primary spring along with rpm's in check I can make a better comparison. As of right now I will say I think the 14.5's are better but I don't think they are worth the extra $90 so I'll probably end up sending them back also. Again I'm going to wait for the right snow conditions to make up my mind for sure.

-Justin

summitboy · Jan 21, 2011

Keep the 14.5's you will need them when you turbo that unit. They are better imo than the 16.5's.

justinkredible56 · Jan 21, 2011

summitboy said:
Keep the 14.5's you will need them when you turbo that unit. They are better imo than the 16.5's.

Well, this is what I worked out in my head. There is a possibility that the rollers are shot, I doubt it, but it's a possibility. I can get brand new 14.5 rollers for 75 vs the 90 I was charged and that would eliminate the possibility they were bad and postpone completely rebuilding my clutches further. Also it would give me some extra spending cash during school and I can't work as much. But...let's be honest...it's probably going right back into the sled, I can't leave anything stock!

I agree the 14.5's are slightly better but by the time I get a turbo I will need new ones and will have to re-invest anyway.

I still haven't decided one way or another. I don't think I've given all components a fair shot yet without all of my different variables to play with on the hill and in the right snow conditions.

It looks like I might be wrong in thinking they were the 15.6 rollers on there originally. The Yamaha parts catalog lists my sled as having the 16.5's like you said. I don't have a caliper up here at school or I would check them.

Summitboy I appreciate your input. I'll work on getting us some more answers today.

-Justin

summitboy · Jan 21, 2011

I highly doubt the rollers are damaged. Just check and see if there is any play in them (with in spec). I have never replaced a set yet. This ain't no SkiDoo junk your dealing with LOL

justinkredible56 · Jan 21, 2011

summitboy said:
As M5 said you are way off.

I would try something close to the Apex setup because you are similar in HP and track size. That pipe does add some HP but not much. If your at 145 HP i would be surprised. Do you still have your stock weights ? They should be 8FS-00 unloaded.

The stock Nytro MTX is as follows

8FS-00 unloaded (65.5 grams)
Now with the 8FS almost loaded (70.9 grams)with the white spring you are very similar to the Apex setup other than the helix and primary spring according to the TY clutch info. The 8FS weights are kind of square. You could buy a set of adjustable primary weights which would be convenient and will cost a little.

summitboy said:
Sounds good. I would like to know the weight of your 8FS. You will get a little closer once you put the B-W-B spring. I would scotchbrite the sheaves and go for a good run and re post the pics.

Once you get the Daltons you most likely will go down in weight a little due to the profile. I bet you will be around the 65 gram range with the Daltons.

Stop and feel clutch heat as well.

I too don't break belts in. Put em on and abuse them ! 45 bucks US is cheap !

Just weighed my weights on a brand new digital scale and they came out at 76 grams a piece. They have rivets in all 3 holes.
So I'm kind of excited...If I'm pulling that much weight and am not THAT far off on RPM's I'm thinking I have the advertised horsepower that I was hoping for... Feel free to bring me back to reality!

I'm going to drop some weight in the weights and see what happens.

Here's some pictures of the clutch sheaves after I broke in my belt last night. Looking a LOT better. I think I'm 95% there thanks to your guys help!

summitboy · Jan 21, 2011

Interesting. Are those what came in your sled ? The Nytro weights stock are empty 8FS-00 (65.5grams) Those are fully loaded im guessing with 13.9 rivets which are 3.6grams each for a total of 76.3 grams. Thats pretty heavy for a stocker. I would try them with the new B-W-B spring once you get it. Your gonna be close for sure. You might have to lighten them up a little due to the B-W-B being a little softer than the G-W-G.

If your not reving to your WOT goal then start by taking out one rivet, maybe the inner one. I bet that will be bang on the money.

Your pics look pretty good to me. Thats looks normal for primary ride height and the secondary looks a lot better as well.

Good to see thus far !

justinkredible56 · Jan 21, 2011

summitboy said:
Interesting. Are those what came in your sled ? The Nytro weights stock are empty 8FS-00 (65.5grams) Those are fully loaded im guessing with 13.9 rivets which are 3.6grams each for a total of 76.3 grams. Thats pretty heavy for a stocker. I would try them with the new B-W-B spring once you get it. Your gonna be close for sure. You might have to lighten them up a little due to the B-W-B being a little softer than the G-W-G.

If your not reving to your WOT goal then start by taking out one rivet, maybe the inner one. I bet that will be bang on the money.

Your pics look pretty good to me. Thats looks normal for primary ride height and the secondary looks a lot better as well.

Good to see thus far !

Those are the stock weights that came in it. I never touched them until now! I think those are the 3.6's also. I went and bought (3) 3.1g rivets that I'm going to throw in.

For some reason my primary spring didn't show up today so I won't be able to throw it in until Tuesday.

I've kind of had a change of heart on the 14.5's and think I might keep them...

So I guess we now know what made me post this thread: http://www.snowestonline.com/forum/showthread.php?t=214216
which is what led me to purchasing the custom clutch kit.

Oh well if it wasn't for all of the problems I've had I wouldn't know anything about clutching!

summitboy · Jan 21, 2011

Don't change anything until you get the BWB. See what happens. Then if you need to reduce drill one of the 3.6 out first then retry. Try to minimize the cost in change LOL. If it over revs when you drill the one 3.6 out then add one 3.1 to where you had the 3.6. Then keep going. No point wasting good rivets if you don't have to.

Linc · Jan 21, 2011

If you carefully punch the rivets out instead of drilling them, you can reuse em.

justinkredible56 · Jan 21, 2011

Well here's an update for everyone. I set the weights at 73 grams a piece. It tached PERFECTLY and was running like a raped ape! BUT I tried climbing a VERY steep hill and about 20 feet from the top the track spun out on the ice and I bailed. I didn't think about killing the motor when I jumped off and I haven't saved up enough money for a Roll/over +tether kit. The sled slid backwards for ways and then starting rolling sideways and finally endoed a bunch. Total it probably rolled for about 150 yards. I'm pretty sure it's totaled.

I will talk to the insurance company on Monday and hopefully they will help me out or else I'm screwed.

I appreciate everyone's input everything seemed to work perfectly tonight but luck just wasn't on my side tonight.

-Justin

summitboy · Jan 22, 2011

Oh no ! After all that ! Sorry ! That sucks !

Linc · Jan 22, 2011

Oh crap! That really does suck, at least you have insurance and you didn't get hurt.

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Nytro belt issues please help

acutah

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Linc

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justinkredible56

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