Polaris RMK 800, 155 track, $400. Engine needs lots of help. Looks like the driveshaft may have broke and been replaced. The inside of the tunnel was a bit beat up and the front arm on the rear suspension was tweaked. For the price, I was ecstatic. “One man’s trash is another man’s treasure”. I stared at it on the trailer for a week or more speculating what I was going to do. I finally decided that I would use the entire tunnel, rear suspension, tank and seat in stock form. I’m not going to narrow this tunnel or track. I’m going to run it as is. From my experience, I feel confident the wide track will be fine for a snowbike.
I dumped it in my shop and started removing parts. As I did, I started thinking that maybe I could use the bulkhead and keep the engine where it is. I quickly realized this won’t work for my design. First, the bulkhead is way too low. For a snowbike, I figure you need at least 12” of clearance between the bottom of the frame and the ground. The Unicorn has 13.5” of clearance. The second thing I noticed is that the engine is shifted off to the rider’s left side of the sled so that the primary clutch sticks out past the tunnel. This wouldn’t do. The bulkhead had to go.
Before tearing the engine out and removing the bulkhead, two CRUCIAL measurements were needed. First, a measurement of how much the secondary clutch is offset from the primary clutch. This can be adjusted once the jackshaft is in place but you need to be close to start.
The second measurement and probably the most important is the distance between the primary and the jackshaft. This needs to be dead on.
I removed the bulkhead which was not all that easy. Freaking glued on. Next I stared at the handlebars and frame that attaches to the tunnel. I tried to envision using them by connecting a linkage arm from the stock handlebars up to the triple clamps on the dirt bike frame. Similar to the Snowhawk design. I soon scrapped this as well. Much more simple to just use a pull-back riser off the dirt bike triple clamps.