Anyone Else??

[steiner]

Has anyone eles had their rails crack at the rear pivot??
Thinking of welding an extra plate along the rail to reinforce it.
Thots.

 

[attaker28]

my attak did but it was still under warranty so they replaced it and updated the W arm. I don't know how long it was cracked before I noticed it.

 

[Ding]

Yes this seems to be a problem with the mono when ridden hard in rough conditions or jumped. I am convinced that it is mainly lateral weakness and not longitudinal weakness that allows it to crack. I am no expert, but the problem with welding unless you really know aluminum heat treating well, is that it can significantly weaken the rails in the heat soaked area. Some things that seem to work well include, reinforcing (without welding), reinforcing with careful welding so that minimizes heat soaking of the adjacent area, or new rails (especially 7075 rails like Ice Age). I am currently using the reinforce without welding approach and having good luck. I actually used a couple short pieces of Stainless (watching out for galvanic corrosion). I have some non-cracked rails coming that I am going to change the reinforcement part (extending it past the pivot mount point) and add a cross shaft to reinforce it laterally as well. My hope in the future is to go with extended Ice Age rails, but of course this involves a new track, etc. and gets quite pricey.

Also, do some searching as there are some old posts about this issue.

Good Luck and let us know what you do and how it works.

 

[Ding]

Here is a pic of my reinforcement plate . . .

 

[Ding]

Here is my original rails with cracking . . .

 

[HighSpeedLowDrag]

Ding is right about the side load being the problem. The 136" length suspensions nearly all do this because instead of spreading the distance between the front and rear arms like on the long track Pro Action the extra length was added behind the rear arm. Replacing those individual idler wheel mounts with a solid mount all the way across helps box this area, as well as adding the reinforcement plates as shown in the picture before the cracks form is important.

 

[welterracer]

Everyone on here expects way too much from a snowmobile.... these are very heavy sleds and they see a ton of pounding

I have had many snowmobile rails welded... just make sure they grind the crack and fill-it weld it... Most shops will charge you between 25 and $50 to weld it

 

[SnowBandit]

I have a set of rails that I cracked big time. I dumped the whole rear skid as I cracked the arms even with the beef up kit done to them. M20 Air wave and it seems to be holding up ok now. I not a easy on the machine. I weight at 300.

 

[ranger1]

Everyone on here expects way too much from a snowmobile.... these are very heavy sleds and they see a ton of pounding

I have had many snowmobile rails welded... just make sure they grind the crack and fill-it weld it... Most shops will charge you between 25 and $50 to weld it

I am going to have to go with Ding on this one because welding a weak spot, (common problem) is not the answer, re-enforcing to make stronger would be a better solution.

 

[steiner]

Everyone on here expects way too much from a snowmobile.... these are very heavy sleds and they see a ton of pounding

Not complaining.
Just seeing if this is somewhat common and what is a good repair.
Right now I have bolted on a piece of SS just like Ding did. Had a piece of unknown grade of aluminum bolted in. That lasted 600 miles and then broke.
Was not expecting the season to last soo long here otherwise I would have removed the skid and had it tig welded by the local machine shop.
Looks like we have alteast another week or two of riding. Did 200 miles yesterday in the Pembina Valley where I ventured off trail to play in a tree line.
Found out the snow was more than waist deep.

 

[Yamahammer485]

Common problem, old problem..

http://www.ty4stroke.com/viewtopic.php?t=54354&start=15

Check out my pics!

 

[sherlock29]

yep i welded a plate on the outside like the pic above. Held up great!

 

[yamaha1973]

Does the plate have to be welded? Or will bolting work? I just picked up a 136 mono and thinking about adding this reinforcement.

 

[sherlock29]

I would weld... stronger. But if you want to bolt it would still be better than stock.