I want to put a 144 under my zr 800
it is a 121 now and is a cross country
I was just wondering if you guys think i should put on new rails
or is there some really good kind of extenions out there somewhere
also where is a good place to get a tunnel extension
thanks guys
Full Version: Stretching a ZR
hey
Here's a write up i found on line about converting a 2001 zr 800 into a 136".
Before I committed myself to this project, I asked as many questions as I could, to gather as much info as possible to make the job easier. I contacted shops out West, PM’d guys on the web sites and did whatever else I could think of to gain some insight. While some people did offer some insight, none of it was as in depth as I would have liked. So a lot of the project was a learning experience for me.
The first decision was how to attain all the parts necessary. I figured there are basically 3 options. Naturally, I chose the most difficult one, but I know I saved a few bucks along the way and still have a solid setup.
Option 1: Arctic Cat offers a complete kit that provides all the parts necessary right down to the rivets. But it comes at a cost. The best price I could get from a dealer for the whole kit was a little over $600, which does NOT include a track.
Option 2: Purchase rail extensions from someone like Tracks USA, then buy the tunnel extension and all the other parts from the dealer or individuals. While this would also save money over the kit from Arctic Cat, I wanted to have solid rails instead of extensions.
Here's a write up i found on line about converting a 2001 zr 800 into a 136".
Before I committed myself to this project, I asked as many questions as I could, to gather as much info as possible to make the job easier. I contacted shops out West, PM’d guys on the web sites and did whatever else I could think of to gain some insight. While some people did offer some insight, none of it was as in depth as I would have liked. So a lot of the project was a learning experience for me.
The first decision was how to attain all the parts necessary. I figured there are basically 3 options. Naturally, I chose the most difficult one, but I know I saved a few bucks along the way and still have a solid setup.
Option 1: Arctic Cat offers a complete kit that provides all the parts necessary right down to the rivets. But it comes at a cost. The best price I could get from a dealer for the whole kit was a little over $600, which does NOT include a track.
Option 2: Purchase rail extensions from someone like Tracks USA, then buy the tunnel extension and all the other parts from the dealer or individuals. While this would also save money over the kit from Arctic Cat, I wanted to have solid rails instead of extensions.
Option 3: I went with the final option. I purchased a used, complete 136” skid and stripped it. This was definitely the most time-consuming part of the job. I purchased the skid, Cat tunnel extensions and bumper from my dealer, TripleE Sales.
After pulling the stock 121”, I took tons of images of both skids for reference for later when I would be trying to put the 136” together. It was also helpful to draw each skid on paper and write down measurements, such as distances between wheel locations, etc. I had to drill about half a dozen holes in the 136” rails to accommodate the 121” parts and keep the geometry in check. The biggest difference was where the rear part of the front arm attaches to the rails. The 136” arms are set up with the fiberglass preload option and they’re not needed for this conversion. I ended up using none of the 136” arms or idlers.
I used the stock ZR front and rear arms that came from Cat’s coupling kit. I used all the idlers and shocks from the 121” ZR skid. While it was apart, I prepped all the arms and painted them with some Cat green paint. One of the toughest parts of this job was removing the upper idler wheels from the front arm since I didn't have a puller. Once I found and removed the C-clip on the back of the wheel, it was fairly easy to tap the wheel off the bearing, then pound the bearing off the axle. Installation was a little different. I put the wheel on the bearing, then used a piece of pipe that had just a little larger ID than the axle and hammered the bearing/wheel back on.
After pulling the stock 121”, I took tons of images of both skids for reference for later when I would be trying to put the 136” together. It was also helpful to draw each skid on paper and write down measurements, such as distances between wheel locations, etc. I had to drill about half a dozen holes in the 136” rails to accommodate the 121” parts and keep the geometry in check. The biggest difference was where the rear part of the front arm attaches to the rails. The 136” arms are set up with the fiberglass preload option and they’re not needed for this conversion. I ended up using none of the 136” arms or idlers.
I used the stock ZR front and rear arms that came from Cat’s coupling kit. I used all the idlers and shocks from the 121” ZR skid. While it was apart, I prepped all the arms and painted them with some Cat green paint. One of the toughest parts of this job was removing the upper idler wheels from the front arm since I didn't have a puller. Once I found and removed the C-clip on the back of the wheel, it was fairly easy to tap the wheel off the bearing, then pound the bearing off the axle. Installation was a little different. I put the wheel on the bearing, then used a piece of pipe that had just a little larger ID than the axle and hammered the bearing/wheel back on.
While I was working on the skid, Ecopter (my friend Jon) was busy up front removing the chain case to get to the jack shaft. We put the new 1.25” RIPSAW track around the jack shaft and put it in place. Getting the speedometer drive side back together is definitely a two man job. On the other side of the belly pan, Jon noticed the starter rope was digging into a couple wires. These wires are tied to the coolant hose coming in from the tunnel, probably wiring for the brake light. The rope only worked through the protective jacket around the wiring, so no real harm done yet. I was able to slide the tie and wiring around to the other side of the hose, keeping it out of the rope’s reach.
For a change of scenery after I had the skid assembled, I started taking the tunnel apart. This was fairly easy but the ease of the job depends on using the proper size drill bit to remove the old rivets. At first I used too small of a bit and I had to go back with a larger one. There are two nuts in the rear storage compartment that hold the seat to the tunnel. There are also two screws up front that hold the seat to the tank. You have to lift the seat up a bit to find these screws, but it’s well worth it. If you don’t remove these two screws you'll end up pulling the tank out of place when you wiggle the seat loose to access all the rivets. That doesn't cause a big problem, but it’s a little tough getting the gas tank back in to position up near the handlebars. It's definitely better to separate the seat from the tank first. It’s pretty obvious which rivets need to come out once the seat is off and you realize that the rear part of the tunnel is just an extension itself.
For a change of scenery after I had the skid assembled, I started taking the tunnel apart. This was fairly easy but the ease of the job depends on using the proper size drill bit to remove the old rivets. At first I used too small of a bit and I had to go back with a larger one. There are two nuts in the rear storage compartment that hold the seat to the tunnel. There are also two screws up front that hold the seat to the tank. You have to lift the seat up a bit to find these screws, but it’s well worth it. If you don’t remove these two screws you'll end up pulling the tank out of place when you wiggle the seat loose to access all the rivets. That doesn't cause a big problem, but it’s a little tough getting the gas tank back in to position up near the handlebars. It's definitely better to separate the seat from the tank first. It’s pretty obvious which rivets need to come out once the seat is off and you realize that the rear part of the tunnel is just an extension itself.
Thankfully, I was laying in bed one night and it hit me that by going with the longer rails, the distance between the front and rear arms has increased. This means that the rear arm of the skid would not mount in the same hole it did before; what do I do now? I measured the distance between the rear arm location and the front arm location (thank God for those measurements I took before dismantling everything) on the new skid and it increased by 6”. I removed the mounting plate from the inside of the tunnel that the rear arm bolts to. While it was out, I painted it too. Because of the numerous mounting holes in this plate, I only had to move the plate back 4.5”. I was lucky enough to realize that while moving this plate back, it was also being moved higher because of the tunnel’s design. I made sure to use a hole that compensated for this. In a picture of the finished tunnel, you can see how the new bolt is closer to the running board than the old hole is. One thing to note here is a rivet should not be within an inch or so of this new mounting hole since the back side of the rivet will prevent you from getting the skid in place later (thank goodness for the Dremel grinder)!
The plate lined up with some of the original rivet holes so I temporarily secured it with a couple screws and nuts and used it as a template to drill the rest of the holes. Once I repeated this for the other side, I set the new tunnel extension in place to see how it lined up. I lined it up with some of the existing holes, then drilled the rest of the holes using the new extension as a template. All of this went very smoothly.
It is very important not to secure all the rivets for the mounting plate as I think some of the plate and the tunnel extension will use some of the same rivets. I was told to use 3/16" rivets, but they are only used on top of the tunnel, to secure the heat exchangers. The rest of the tunnel requires 5/32" steel rivets, which were a little difficult for me to find.
One thing I had to deal with under the tunnel was the protector plate for the crossover hose for the heat exchangers. The original plate has an angular design and was held in place with three rivets to the top of the tunnel and three rivets to the rear of the tunnel. Because I opted not to use the longer heat exchangers, I had to do something different here. Ecopter took a piece of aluminum and formed it in a U-shape. This fit around the hose and I riveted it entirely to the top of the tunnel. Most of the guys I spoke with realized the longer exchangers are not necessary; time will tell for me, and I hope they’re right.
It is very important not to secure all the rivets for the mounting plate as I think some of the plate and the tunnel extension will use some of the same rivets. I was told to use 3/16" rivets, but they are only used on top of the tunnel, to secure the heat exchangers. The rest of the tunnel requires 5/32" steel rivets, which were a little difficult for me to find.
One thing I had to deal with under the tunnel was the protector plate for the crossover hose for the heat exchangers. The original plate has an angular design and was held in place with three rivets to the top of the tunnel and three rivets to the rear of the tunnel. Because I opted not to use the longer heat exchangers, I had to do something different here. Ecopter took a piece of aluminum and formed it in a U-shape. This fit around the hose and I riveted it entirely to the top of the tunnel. Most of the guys I spoke with realized the longer exchangers are not necessary; time will tell for me, and I hope they’re right.
Before riveting it all together, I was able to remove the decal from the tunnel and use it on the new extension (a hairdryer did wonders for this). I riveted it all together and only put one scratch on the tunnel, which can be easily buffed out.
Now came the time I was dreading for a while, getting the skid into the tunnel. Because I was impatient, I had to do this on my own. After playing with it for 30 minutes or so with no success, I used the same method as when I pulled the skid from my ZRT by myself, tipped the sled on it’s side. This is definitely the only way for a person to get a skid in by himself. This is when I realized one rivet on each side of the tunnel was too close the mounting hole for the rear arm. After about an hour, I had the skid in place and ready to be tightened down. Getting the sled back on it’s bottom really requires two people, unless you can put something under the rear of the track so the weight of the sled does not transfer to the new tunnel extension, forcing it to the ground as the sled rolls over. I thought I ruined it all as I heard the tunnel extension meet the concrete, but no damage was done.
I then put the new bumper on. Holes exist in the tunnel extension for the bumper, but the forward holes lay over the old tunnel, so I had to drill those holes out (no big deal). After securing the bumper, I snapped in the rubber strip to give it a finished look and cover the four bolts that hold the bumper in place. Then I installed the original snow flap with the original nuts and bolts.
Now came the time I was dreading for a while, getting the skid into the tunnel. Because I was impatient, I had to do this on my own. After playing with it for 30 minutes or so with no success, I used the same method as when I pulled the skid from my ZRT by myself, tipped the sled on it’s side. This is definitely the only way for a person to get a skid in by himself. This is when I realized one rivet on each side of the tunnel was too close the mounting hole for the rear arm. After about an hour, I had the skid in place and ready to be tightened down. Getting the sled back on it’s bottom really requires two people, unless you can put something under the rear of the track so the weight of the sled does not transfer to the new tunnel extension, forcing it to the ground as the sled rolls over. I thought I ruined it all as I heard the tunnel extension meet the concrete, but no damage was done.
I then put the new bumper on. Holes exist in the tunnel extension for the bumper, but the forward holes lay over the old tunnel, so I had to drill those holes out (no big deal). After securing the bumper, I snapped in the rubber strip to give it a finished look and cover the four bolts that hold the bumper in place. Then I installed the original snow flap with the original nuts and bolts.
From this point, it was just a matter of cleaning it up and adjusting the track's tension. This was a slight problem since I installed the coupling blocks. I used the template included with the kit, but the track tension bolt still interfere with the bolt for the block. I rounded off the outer edge of the block's bolt head to make it work. This is something I'm not really satisfied with and will spend more time to make this fit better. As the track stretches and I have to tighten it, these bolt heads will conflict with each other even more. The simplest solution is to use a bolt on the blocks that has a standard head (thinner head), compared to the hex bolt Cat uses. I still have to figure out if I did something wrong here. Hopefully some other owners can tell me if their bolts are this close too.
Now we just need snow so I can see if it all works. Almost everyone I've spoken with that has a 136" sled said they wouldn't go back to 121" and I feel I will have the same opinion. I started down this road because I needed a lot more traction than I was getting from the 121” skid and stock track. In line with the longer wheelbase theory, the longer skid has to allow the sled to ride over some moguls that the shorter skids fall in to.
Hopefully I put it all back together right and I'll enjoy this new setup.
Now we just need snow so I can see if it all works. Almost everyone I've spoken with that has a 136" sled said they wouldn't go back to 121" and I feel I will have the same opinion. I started down this road because I needed a lot more traction than I was getting from the 121” skid and stock track. In line with the longer wheelbase theory, the longer skid has to allow the sled to ride over some moguls that the shorter skids fall in to.
Hopefully I put it all back together right and I'll enjoy this new setup.
talk to vanamburg and get one of their tunnels. they make killer stuff, money well spent.
Get ahold of www.avid-products.com
I called them up, and they had all the parts I needed to do the track swap on my 900.
I got the rail extension 151" to 159" with the big wheel offset.
The track was $25.00 more than www.tracksusa.com , so no big deal. The owner was more than happy to help out with any questions that I had. We tore the sled apart, and had it back together in 6 hours. I got some pretty detailed instructions off the internet, and we just followed them. I could do the swap now in 3 hours.
I spent $700.00 with Avid, and sold my 151" for $250. So I'm into the whole swap for $450.
DK
I called them up, and they had all the parts I needed to do the track swap on my 900.
I got the rail extension 151" to 159" with the big wheel offset.
The track was $25.00 more than www.tracksusa.com , so no big deal. The owner was more than happy to help out with any questions that I had. We tore the sled apart, and had it back together in 6 hours. I got some pretty detailed instructions off the internet, and we just followed them. I could do the swap now in 3 hours.
I spent $700.00 with Avid, and sold my 151" for $250. So I'm into the whole swap for $450.
DK
Here is my ZR900sp 121 converted to a 136"
My next project to shorten a 162" King Kat to a 144" trail sled
My next project to shorten a 162" King Kat to a 144" trail sled
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