I got this info from Sledjunky through stoy. Sledjunky said it was ok to post it up, so here you go...
As many of you AC guys know, there have been a number of threads on different suspension set ups for the MCs. I tried the ZR rear arm mounting deal, which I preferred over the stock set up, but a lot of guys don't care for the excessive weight transfer that the sled has with that set up. Stoy hinted about a set up that Sledjunky did to his sled so I bugged him until I got the goods and did it to mine.
What you want to do is relocate the front arm of the rear suspension to the set of holes (they're already there in the rails) that are 2-3/8" farther back than the stock spot, move the limiter straps rearward, relocate the front arm bump stops and front arm shock lower mounting point, cut the long ends of the rear springs, relocate the rear spring slide blocks, do a little whittling on the rear of the rails, install ten-tooth drive sprockets, and finally, install gearing that accounts for the larger diameter drive sprockets.
This does not require a drop and roll. The track clears the front of the tunnel and the heat exchangers just fine. It may slap the tunnel exchangers a bit when the front is fully compressed, but not enough to be any concern.
The parts you'll need are:
(2) ten-tooth drivers that fit a 1-1/16" hex shaft drive axle.
(1) nineteen tooth top sprocket.
(1) forty three tooth bottom sprocket.
(1) 72 pitch chain.
(as required, 8 oz I think) chain case oil
(4) rivets for the front arm bump stops. (I can't remember what size they are. I had plenty lying around in my rivet stash)
It's all a pretty straightforward deal that the pics should explain for the most part (they're worth a thousand words, you know...)
The only real measurements that are even 1/2 way critical are how much material you remove from the rear of the rails, how far you extend the rear axle slot forward (both are to account for the fact that more of the track is now being used up by the drivers) and finally, where you locate the hole for the rear spring slides.
I extended the rear axle slot forward to a point where the front edge of the slot is even with the rear edge of the axle adjuster bolt block. You may not need to go quite that far, but once I had everything set up in the mill, I didn't feel like having to do it over. I've been told that you only need a quarter inch, but that seemed a bit tight to me. If you don't have access to a mill then you can hog it out with a die grinder and a bit for cutting aluminum. Just be careful to keep the top and bottom of the slot parallel to the rail on the horizontal plane.
As for the rear edge of the rail, I removed about 3/8". I just hacked that off in the mill too. Just follow the original contour of the rail all the way down the bottom part that's angled forward to the where the hyfax goes over the "I beam" section of the rail. I touched up the radius of the curves on a belt sander after I was done milling it. I guess you could use a hacksaw, a sidewinder, or a belt sander, to remove all the material, but that might take a while. Anyhow... The reason this is important is so that the track clips don't hit the back of the rail. Since the ten-tooth drivers are going to take up more slack than the original nine-toothers did, your axle will be further forward in the slot than it was.
I found that my final rear axle adjustment with the track properly tensioned (and I run it a little on the loose side) was pretty damned close to where the front edge of the axle slot was before extending it forward.
It was easier for me (working by myself) to reinstall the rear suspension with the rear axle and idlers removed from the skid. Then just install the axle, wheels, spacers, etc. after you've got the front and rear arms mounted to the tunnel.
The hole for the rear spring slides needs to be marked and drilled in the rails. Simply follow along a horizontal plane on the center of the holes that the front suspension arm brackets mount to. Measure 2-3/8" back from the rearmost existing 5/16" hole. Mark, center punch, and then drill a 3/8" hole in that spot. You'll want to cut off the extra length that the rear spring sticks out past the slider block. If I remember correctly, I think I cut off about 2-1/4". Just mark it and cut it so that there's only about a 1/2", or so, of the spring sticking out past the slider block.
The hole where the front arm is going to mount in the tunnel is already present in the reinforcement "doubler" that's riveted to the tunnel. Simply drill out the upper hole in the rearmost spot. The doubler plate makes for a great drill guide when you drill from inside the tunnel.
The limiter straps will go on the rear cross brace at the front of the rails. I guess you can toss the front cross brace, but I left it there for extra support. (See pic)
The lower front shock mount will go to the holes that are already in the rails, 2-3/8" further rearward than where it was in the stock position. (See pic)
The front arm bump stops move back to the set of holes right behind where they were located from the factory. (See pic)
I'm not going to get into removing the drive axle and pressing the drive sprockets, blah, blah, blah... I figure if any of you can't handle that part on your own, then you probably shouldn't even attempt this project. It took me 2 evenings after work, working at a fairly leisurely pace, checking things while I went along, to complete this project.
While I've tried to be fairly comprehensive, I'm sure I probably left out some critical bit of information. Feel free to ask if there's something I didn't explain well enough. Good luck to those that go ahead and do this mod. It's well worth the effort. I'm sure Sledjunky and stoy will back me up on that. I'm also sure they'll see this thread and correct me if I screwed up on any of the instructions. Constructive, corrective criticism is welcomed.
Thanks to Sledjunky and stoy for the info in the first place.
