biglines
Newbie
Now that we are having some spring conditions and in our area we have had 70+ inches of snowfall this winter i have been boondocking any chance i can get. The belt heat from riding this way with my current clutch setup is way too high. My setup:
2011 nytro xtx, stock motor
1.75 backcountry track
20/39 gearing
stock 9 tooth driver
stock primary weights/ blue/silver/blue spring
stock secondary 43 degree and white spring 70 degrees
The conditions to me say that there is an increased load and i could use more belt grip in the secondary. Both clutches are getting very hot. This is where i am confused, i tried a straight 41 helix/ 70 degrees of spring wrap and only notice a drop in rpm 200 and the same amount of heat. So i figured i needed to add more belt grip and i put in a 42/35 helix with 70 degree wrap and my rpms dropped another 3-400 rpm! and the clutches are still very hot! whats going on? these changes should be adding rpm, i am at a loss at this point.
Anyone else see this happen before? My next move is going to put back the 41 degree helix and i am going to drop some weight or add spring in the primary and see if i get some results in reducing the temperatures.
2011 nytro xtx, stock motor
1.75 backcountry track
20/39 gearing
stock 9 tooth driver
stock primary weights/ blue/silver/blue spring
stock secondary 43 degree and white spring 70 degrees
The conditions to me say that there is an increased load and i could use more belt grip in the secondary. Both clutches are getting very hot. This is where i am confused, i tried a straight 41 helix/ 70 degrees of spring wrap and only notice a drop in rpm 200 and the same amount of heat. So i figured i needed to add more belt grip and i put in a 42/35 helix with 70 degree wrap and my rpms dropped another 3-400 rpm! and the clutches are still very hot! whats going on? these changes should be adding rpm, i am at a loss at this point.
Anyone else see this happen before? My next move is going to put back the 41 degree helix and i am going to drop some weight or add spring in the primary and see if i get some results in reducing the temperatures.
terez
Expert
Slow vehicle speed, high ambient temps, heavy snow load.....
Yer problem is as much or more underhood/clutch area heat as it is the actual clutching.
For these conditions you need to vent the cab and clutches significantly.
The Nytro runs Very hot under the hood even in cold winter temps with good vehicle speed......
Aftermarket vent kits everywhere you can are nec.
Also don't forget to look at gearing as much or more as clutching. Gearing down will be a huge help for the clutches working in their proper ratios and make it a lot easier for the sled to initially get moving and accelarate. The old saying "don't fear the gear" is way true.
Most trail sleds need to drop a tooth or even two on the top to work well off trail.
Amazing how many riders will off trail ride a trail sled....and then bitch about belt life and shitty performance on a sled geared to run over 100mph.
Yer problem is as much or more underhood/clutch area heat as it is the actual clutching.
For these conditions you need to vent the cab and clutches significantly.
The Nytro runs Very hot under the hood even in cold winter temps with good vehicle speed......
Aftermarket vent kits everywhere you can are nec.
Also don't forget to look at gearing as much or more as clutching. Gearing down will be a huge help for the clutches working in their proper ratios and make it a lot easier for the sled to initially get moving and accelarate. The old saying "don't fear the gear" is way true.
Most trail sleds need to drop a tooth or even two on the top to work well off trail.
Amazing how many riders will off trail ride a trail sled....and then bitch about belt life and shitty performance on a sled geared to run over 100mph.
biglines
Newbie
Typo on my first post. My gearing is 20/39. i dropped one tooth on top when i installed the track. I have considered dropping another tooth 19/39 but i am not sure if i can with the 68 link chain currently in there. Anybody know if 19/39 is alright with this chain?
johnelway
Expert
Here from the manual. so 19/39 will be ok with the stock chain!
biglines
Newbie
Nice! Now i just need to figure out 19 or 18 tooth!
So is the consensus that i am losing rpm when using less helix related to being over geared for the conditions?
So is the consensus that i am losing rpm when using less helix related to being over geared for the conditions?
johnelway
Expert
just to let you know.
i'm running 21/39 stock
i have the ulmer kit (k&n, PC5, Hindle exhaust)
my clutch was running hot but i compared with my friend stocker and he was hotter than me.
So i just put some frogskinz in front of the clutch.
Do you have a problem with your belt or only the heat?
Cause i found that my nytro was running the belt too high in the secondary and this has cost me 5-6 belt in the last 2 season.
Just removed the 3 washer behind the secondary and problen solved. No more belt since 1500 km
i'm running 21/39 stock
i have the ulmer kit (k&n, PC5, Hindle exhaust)
my clutch was running hot but i compared with my friend stocker and he was hotter than me.
So i just put some frogskinz in front of the clutch.
Do you have a problem with your belt or only the heat?
Cause i found that my nytro was running the belt too high in the secondary and this has cost me 5-6 belt in the last 2 season.
Just removed the 3 washer behind the secondary and problen solved. No more belt since 1500 km
herndonp
TY 4 Stroke Guru
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Check your clutch offset as well. If they are not aligning properly you will generate a lot of heat. Also blow the clutches out with compressed air as these stock belts will create a lot of belt dust. I blew mine out after 500 miles and couldn't believe the dust cloud and the belt looks fine.
Pete
Pete
biglines
Newbie
My belt life has been good. i have put on 1100 miles plus the miles the previous owner put on 200-500 miles? so this last belt i have blown in these conditions is not exactly new. I do know the heat that the clutches and belt have been seeing lately in these conditions is not good! I am thinking with the recent conditions i wont see 300 miles with a new belt so that's why i am looking for some solutions. Plus there is the clutching theory part that doesn't make any sense to me...
As for deflection, i only have 1 washer behind the secondary. It falls within yamaha's specs.
As for deflection, i only have 1 washer behind the secondary. It falls within yamaha's specs.
