Blown Belt

[bleedyamaha]

I tightened mine to 70 and it seemed like the sled hit the wall around 100 mph on the grade. Snow was a little loose but something didn't seem right on top end. How could you tell it was binding? Take a look at your secondary spring for paint missing on all sides. At 100 mph your spring is smashed together and trying to twist and rubbing paint as there is no more room.


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[uprider800]

It was binding. That was the wall you hit. If you would of held it longer you most likely would have blown a belt or at least put a lot of belt on your secondary as it got hot.


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Ya i figured why keep it pinned when it's not really going anywhere. Now if I rolled into the throttle it would build power easily and do 80 half throttle. We will have some fresh snow on the lake by mon night and can test again. I never checked belt or clutch temps but I noticed belt dust on the secondary and had black ring in my primary. I cleaned clutches and shimmed my belt deflection as it was to loose from the dealer setup.


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[newtron]

You can add .060 thick washers to the tower bolts before putting helix on. Just make sure the washers done get pinched crooked, sometimes you have to grind a small flat on them. Or better yet get the spring pocket on your secondary machined.


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his

Does this reduce the spring tension in the secondary as well?

 

[jonlafon1]

EDIT
My bad I answered for another poster(shag).. Just noticed

 

[shagman]

his

Does this reduce the spring tension in the secondary as well?

Been doing it for years. Not enough to worry about.


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[NOS-PRO]

for those having the pocket in the secondary machined to reduce spring bind...anyone willing to disclose how much material to be removed? I have access to local machine shop with all the necessary equipment, but owner is not a sled head..and will simply take off how ever much I tell him to. And frankly I have no idea haha. Feel free PM me if preferred

.070" is what I have been taking out from the bottom of the spring pocket

 

[1100saber]

.070" is what I have been taking out from the bottom of the spring pocket

thanks!

 

[cannondale27]

All that power I don't understand why you guys just don't gear them higher. No chance of spring bind and the clutches are much more efficient when not shifted out all the way.

 

[snowbeast]

All that power I don't understand why you guys just don't gear them higher. No chance of spring bind and the clutches are much more efficient when not shifted out all the way.

Hey steve,hows the trails? I think you got my package today,at least it said delivered and on porch,not what I paid for,they were suppose to have someone sign for it,so maybe some one will steal it,its insured good lol..

 

[Fleecer]

Did some rr bed riding today......0 degrees. Ran 90-95mph a couple miles, whacked it for 3/4 mile, hit 117mph, backed off to half throttle 95-100 mph for another 3-4 miles. Stopped and checked clutch temp....omg could have cooked an egg on these clutches. Did some trail riding and every me I'd nail it, get a whiff of belt burn. Crossing roads, get whiff of belt burn.

Currently upgraded to 8dn, no doubt it's tougher, but clutches run waaaaaay too hot. Clutches still clean, but appear to be turning darker color everywhere the belt rides front constant slipping and burning.

Does anyone sell aftermarket airfilter. I'd remove that big airbox, drill holes in clutch guard like cheese grater for more cooling.

The way these clutches run hot at 0 degrees, come March....I'll have to park it if temps get above 20.

 

[uprider800]

Did some rr bed riding today......0 degrees. Ran 90-95mph a couple miles, whacked it for 3/4 mile, hit 117mph, backed off to half throttle 95-100 mph for another 3-4 miles. Stopped and checked clutch temp....omg could have cooked an egg on these clutches. Did some trail riding and every me I'd nail it, get a whiff of belt burn. Crossing roads, get whiff of belt burn.

Currently upgraded to 8dn, no doubt it's tougher, but clutches run waaaaaay too hot. Clutches still clean, but appear to be turning darker color everywhere the belt rides front constant slipping and burning.

Does anyone sell aftermarket airfilter. I'd remove that big airbox, drill holes in clutch guard like cheese grater for more cooling.

The way these clutches run hot at 0 degrees, come March....I'll have to park it if temps get above 20.

Can't be worse than the cat turbos in 12 - 13. I could have cooked thanksgiving Turkey on those clutches. Most of the time you couldn't even touch them. Some of those sleds could blow a belt in 50 miles! Also Turbo Dynamics's said putting a different air filter system raised the boost unreal and would need a tune to compensate for it.


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[stevewithOCD]

You see the black mark deep in the secondary...most clear in the 2nd photo? The primary is trying to pull the belt deeper in the secondary and its clearly heating and tensioning the belt at that point in the shift and stalling there. That puts a ton of load on the belt. With the power you're making...the belt has no chance. It doesn't look like full shift to me but if I could hold it in my hand an look at it, I could tell a lot more. Take the secondary in your hand and bolt it together without the spring in. Now open it up and lay the belt down inside and see where it sits, relative to the center hub. If the belt nearly touches the center hub, its good. If it stops short and there's quite a gap there, shim-up the helix by putting washers under the helix before you put the nuts on to hold the helix to the towers. Shim it until the belt nearly touches the hub at full shift and you're done. If its already sitting on the center hub, that's your problem. The belt is getting too far into the secondary and its slipping on the sheaves leaving the black mark. If its good right now, your side load nearing full shift is too high...you're squeezing the belt too much on top end. Remember...you need less squeeze at full shift in the secondary than you need out of the hole and through the low middle. Squeeze should drop enough, not to slip...with the least amount of squeeze possible. Do you understand the Trig for calculating torque feedback, based on the helix angles you're running? Too much angle, along with tall gearing will eat the belt on the shift and get it ahead of the primary for the ground speed of the sled. That puts load and heat on/in the belt...not good. It also requires more time to back shift and if it gets behind the primary returning to the top of the secondary, then you hit the throttle hard and you've got bite, you're going to snap that belt in half quicker than #*$&@. There's so much more to all of this...but suffice it to say, "the pattern I see on your secondary is not happy". Make sure your belt has plenty of DEFLECTION in neutral...if it doesn't and the sled creeps or pulls on the motor in neutral, with the power these things make, your belt will break in short order!

I checked this & I'm 1/4'' away from hub & 1/8'' from bottom of MACHINED sheave. The thinnest washers i have, put my belt cords on edge of unfinished part of sheave so that looks like it will start to fray my belt. I may need machine shims or washers that i don't have for now so i'll put it back & wait for more testing results. I'm 60 mm offset & my belt isn't touching hub so i'll see what happens next 600 miles.

 

[Joe ltx-le]

THis was me. Lol

I really think I fixed the issue though. When the belt blew I could only get about 105. That's when it blew. 8700 rpm 105 mph.

When I got back to the camp I installed the new rollers and set the spring to 6-1. Since then I put on 390 miles. No belt issue. Belt runs cool and I get more top end. Around 115 but never really pushed to any more ( kinda terrifying with all the moose we have).
895 miles on the sled now and really the belt was the only issue.

These secondary's just where not tested At all. My opinion of course.

 

[jonlafon1]

THis was me. Lol

I really think I fixed the issue though. When the belt blew I could only get about 105. That's when it blew. 8700 rpm 105 mph.

When I got back to the camp I installed the new rollers and set the spring to 6-1. Since then I put on 390 miles. No belt issue. Belt runs cool and I get more top end. Around 115 but never really pushed to any more ( kinda terrifying with all the moose we have).
895 miles on the sled now and really the belt was the only issue.

These secondary's just where not tested At all. My opinion of course.

Joe, good to hear you got it dialed in some.. How many studs you running and length? Thanks

 

[Joe ltx-le]

Joe, good to hear you got it dialed in some.. How many studs you running and length? Thanks

144 down the center 1.325. Not near enough length for any sort of bite. I'm just in it for safety.

I think a 1.5 inch track studded up would be ideal.