I did the same thing on a polaris.121-144 I got a set of rails for the rmk. the suspension is different so i welded the holes shut and redrilled the new ones for my extra ten. the problem came that rails are made from the lowest grade aluminum. they also had a different curve on the track approach. I would buy rail extions and go that rout

nothing goes like three holes!!!!!!!

 

if i were to do that wich i owuld like to do for polaris is i would getthe sks rails, stronger but heavier, it would stand up to the beating longer where as the rmk is made light to keep it lighter and is ment to be ussed in deep powder and those rails are easy to bend. the my thoguhts

Ride it like you stole it!

 

Yes you can use rails from 01 MC 600 and it will be much stronger than rail ext.'s and hyfax will go all the back to . If you look at 01 or 02 MC's you'll see they have 2 rear arm mounting position's 121 and 136 for so arm can be moved for personel prefrence.. So all holes are all ready drilled in 01,02 136 rails so they would bolt right in and you could leave your rear arm where it's at so you do'nt need to drill holes in tunnel and it will be as strong as your stock ZR.
But 01 and 02 MC have bigger rear wheels than your ZR so you need to buy new wheels too and I don't think 2 in track will fit because of driver sprockets so you would need to change them also and then you would have to lower the gearing and you need tunnel ext ect. It might be cheaper to buy complete kit from someone. Just depends how much track you want. url]

You can also just move your whole 121 suspension back and mount 136 track and you would have better track angle. All you need is a Tape Measure, Drill and new track.

Go to www.sledbc.com they have a chart to tell you how far to move suspension.

And www.brownsleisureworld.com for Arctic Cat Micro Finch online.

Quit Yer Bitchin, Your Mama 's Not Here and I Do'nt Give A Shit!!!