Started blowing belt Tapex

[Jona$]

So blew my second belt this day, they both went at the same way.

Both started to rip out the cord in the middle of the belt.


Both has happend when doing long wheelies "500m +" in speeds accelarating 150-200kmh

made dragraces etc and its fine.

It has worked flawless with this before but here are mods i belive can have to do with it.

1. stretched it out to 144 from 121. belt slippage sec, locking the belt at higs speed?
2.put on meshkit from xxx-rods, to cold primary and secondary? http://xxxmodrods.com/_mgxroot/page_10798.html

3. a worn engine mount, you know the rubber ones?

 

[Jona$]

No harheaded turboguys out there?

Have it geared down 1 on the over gear but had that for years without no problems.

 

[Boosted Brad]

Secondary springs tend to loose side pressure. I have to change mine yearly!

 

[zal]

What RPMs are you hitting, when was the last time you went over your clutches?

 

[Jona$]

Not hitting the rev limiter, did go through them pre season. It sure must be assosciated with the extending of the track.

 

[Jona$]

well then a long call to Ntc and i was recomended to go down one gear if i liked the 51/43 helix, and the thing is i like having big push in the start.

and if i go for example 45 straight i may need to put on more weight since it will get the secondary to start pulling faster, but then again faster backshift,

As the mechanic explained is that i put alot of strain on the belt since having such a har angle as 51 to start with and aswell the 21/38 gearing, hes deal was putting another gear down and new chain instead of getting a straight 45 since it wouldnt be as aggressive with the 45 at start.

I love its aggressive at start, so i dont now, gonna tear down and se that i was right at the gearing.

what do you guys think?

 

[Jona$]

23/38 was the gearing and a 51/43 helix seems to much. How about 22/38 68l chain and straight 43? Or shockwave straight.

 

[Thistledoo]

How about 20/40 do you really need to go 200 kph?? lol

 

[Jona$]

well Thistledoo, call me crazy but i enjoy wheelies at that speed

But 22/38 vs 20/40 isnt far away isnt it. and a big gear is the same price as a helix so...

 

[Jona$]

So Went with 22t gear, 68l chain and a shockwave helix that i Will start on 43deg

 

[Jona$]

So after installed the 22t i drove around and adjusted the chaintension and went back today to start tuning.

Made a wot at the sea and hit 10500, same as before shifting gear, turned around and made another and could hear the belt ripping apart while climbing up to a wheelie.

the secondary was a bit warmer then the primary, but non of them where warmer then max 40deg celsius.

My setup i had as short 121" and worked flawless and the one i started the winter with as 144

primary:
y-s-y spring "org"
super tip cam x 55g set from the bottom tungsten,tungsten tungsten,3shims 2shims,2shims

secondary:
white-white spring set at 80deg
8bvfa 51/43 org helix

23/38 gearing
9t no slip.

This worked awsome as 121, but as 144 the belts flys as soon as i come in deeper snow and wheelie.

So i put on 3gr on the weights to bring down the rpms to 10500 to be safe, and that didnt helped.
Next was putting in the 22t and that blowed a belt immedatily, but could be the use of earlier setup, but then again?

My next step is start with 70deg ont the spring , 45deg on the shockwave helix and add a 1mm shim on the secondary since i had 16,7mm as offset and 2,3mm as freeplay. 1mm should give 15.7 and 1.3 right between the lines

The cc i still dont know as i dont got the tool for it and couldnt get the primary off since my puller bent from all the years of use, but as i understand the cc never seem to change on this sleds.

As you can see, it seems like it was shifting full on both the primary and secondary when blown, some marks are problaby from the last 2 ones sinces i havent had them apart to clean up all.

 

[summitboy]

Tough call for many guys here because most of them run a mountain setup where as your more of a flatland setup. TY site might be better for that type of a setup.

From looking at your pics i can tell your secondary is not clamped strong enough. I would try a stiffer spring to start if it were me. You only put 11 inches of track down but i went through the same thing when going from a 162 to a 174. Try a Cat green or EPI purple to start. May want a stiffer primary as well. Maybe blue pink blue or even the blue white blue.

Im guessing your shockwave is a straight cut. Roller size ? Try and leave that where it is a change one thing at a time. Not sure if that will help or not.

 

[zebiraross]

The x weights need way more weight in the tip. Put the tungstens in the tip and I bet your belt quits slipping. Those weights need as much tip weight as possible for belt squeeze on top end. The problem with those weights is if you put tungstens in the tip there is a good chance your primary won't initially shift out to get the sled going. Double edge Sword. That's why I got rid of those weights about 4 years ago when I had them. Way to aggressive.

That being said, add as much weight as you can to the tips that will still let the primary shift out from a stop. Or sell them and quit fighting them and get some 60g base weight normal supertips, or Daltons.

 

[Jona$]

22/38 is the same setup as for rtx i belive, this must be kinda good in deep snow? better then 24/38. And yes i run quit alot flatland but my favorite is to avoid the trail and go technical riding and hills.

well this works fore alot of people, the setup with springs etc, so why wouldnt it for me? is the pink sec spring weaker or stronger than wh-wh, know i have one.

aswell how do i know the secondary or primary are slipping or need lower or higer pressure, i never hit the top revs or hear any or feel.

if i also start changing springs all are starting to go south. cant need to change all because of a 121-144.

The shockwave havent i tried yet,just had the 51/43.

Im stressed out of time and believe in a easy solution but looks like it pulls way down in the secondary.. but how do i know what i have to do,, maybee i can get the arctic green spring here in sweden fast.

 

[Jona$]

Zeiberros.

Weird you say that but i understand your theory, all people have diffrent thoughts and idees and i try to manage all.

But as i understand putting that much in top will cause the weights to start pulling in again.

Man i just wanna get this working

cant need to change gearing,weights,springs,helix just because a 121-144 conversion

 

[Mcx Nytro]

I think i know your problem......are you parking close to any 8oo cats?? Can rub off you know..

Seriously looks like you are not getting enough pressure to squeze the belt. In my mountian setup( alittle different I know) i had to use a stiffer spring in the secondary to stop mine from slipping I also had my secondary shaved to create a consistent surface. Not an issue with stock power but when boosted a whole new ball game Hope it helps T

 

[Jona$]

So if i get it the blue pink blue is a bit softer at the start but harder at the end which should make me to take of weight at the supertip?

But the green cat spring, from what? number on it? preload etc?

But it the same time it feels as starting to change it all will screw the next week in the hills up...

Man im worried now...

as i see it the both springs you show is softer then my ysy?
http://www.totallyamaha.com/snowmobiles/aaTECH/drivespecs/primary_springs.htm

and perhaps i need a stiffer one in the secondary but what is the green cat spring, is the something yamaha has to offer?

 

[Mcx Nytro]

I used the cat yellow or red one for the softer snow and the other for set up stuff and Cat springs are WAY cheaper than yami's. IF YOU are slipping on top endaand the spring change won't help(I cannot see that happening) you may use more tip weight. What rollers do you have in the primary??I used the smaller 14.5 to put more belt pressure on it JMO

 

[Jona$]

I also have the 14.5 rollers, wich spring should i try and Primary or secondary? How do i know when a spring isnt to stiff/hard?
For me the picture tell me the secondary looks to go to easy and need a stronger spring

 

[Jona$]

So now i got the green spring in My hand, what should i start at? And My belts are spanking new, do i really need to drive them in before testning

And as for the supertip how about get rid of 2shims in the middle and put in top so instead of 6 it will be 8gr or should i leave it alone`?
And if the green spring will raise or lower rpm, should i take out wights and if so wich part or should i adjust the rpm by turning the shockwave helix?

cleaned up, and sandpappred the sheaves etc.