This post will be without a doubt the most information I will have ever shared with the forum and has changed ice fishing for me, forever. Maybe it can do the same for you. Not sure its sticky worthy as it will be more of a recount of our build and not a guide. I will do my best to answer questions.
Big thanks to my Dad "Swampy" for making this possible.
Without his knowledge and skills in metal fabrication and basically everything I'm not experienced at this project would have never taken off.
Ill try and keep the story short and sweet because I can ramble.
Walking sucks, walking through snow sucks, walking through snow pulling hundreds of lbs of gear so you can enjoy epic ice fishing sucks.
About March of 2017 I found this youtube video.
https://youtu.be/MI0GVSP0fp4I then sent the link to my Dad and said Hey, Ill fund this build if your in because I think this is worth building and not too difficult I think together we can make this happen.
Surprisingly he bites! I then found a donor, Blown up 1991 Polaris classic 500 Liquid /w reverse $100
I wish I had more in the making of photos but I don't we were hard at it in the garage cutting and grinding and dismantling. Basically all you save is the tunnel, the skid the track and a bit of the bulkhead the jackshaft and chaincase and original handlebars.
Everything else needs to go.
Build a simple frame that bolts to the top of the tunnel and attach engine and handlebars to. Modify existing suspension in the skid to remove the natural "rake" a snowmobile chassis has.
Like the youtube video we used the tav2 comet clutch$300+ and later found out that this application is asking a bit too much from that size of clutch and after I
finally understood how everything worked I came to this conclusion, as a result I now use a 72 tooth sprocket that connects the jackshaft to the driven clutch sprocket. This allows the comet clutch to require the least amount of resistance to rotate the jackshaft and make the dog move, Now my gearing is in what I believe to be the correct place, I haven't been able to burn a belt being geared this way.
Gearing was a challenge but finally I was able to learn from mistakes with smaller sprockets and get to where I needed to be. Torque monster and low top speed.
Balance was another challenge, anyone who knows snowmobiles knows how big and heavy chain cases are, full of heavy sprockets and additional ones for reverse. Due to the original location of the chain case on the snowmobile, it is now placed far out from the center of gravity. Engine placement was how we counteracted the weight of the chain case leaning the dog. This was trial and error and we actually changed engines 3 times along the way. Settled on a Princess auto 208cc 7Hp OHV pull start $150 The dog now tracks very straight and doesn't lean one way or the other.
Handlebars were fabbed and welded and attached, youtube video I followed for direction used all original snowmobile controls. I did at first but later changed to more Snowdog like (bicycle) brake levers and an amazon tether kill-switch for safety. Way more control and precision, was a great addition.
Making cables was a tedious job. I made the throttle cable 3 times before it was perfect, Brake caliper I added after from Princess auto $70 was easy to cable up.
Reverse cable going to lever on chaincase from handlebars was difficult because of the incredible tension it has to be under in order for the reverse hand lever to pull it far enough to compress chaincase spring and pull the reverse sprocket in to mesh with others.
Built the cowl out of some corrugated plastic and pex pipe as a frame, Very lightweight and makes it look a little more bad a$$, Really all it does is deflect snow and air. I still need to fasten this with a hinge to the front hahah.
In conclusion, this build has been a ton of fun for my Dad and I. Challenging at times and simple at others. I enjoyed all the hours in the garage, dreaming up ideas and solutions to problems and building something from not a whole lot. Just a video of what it could be and figure out the rest as we go. Good times!
We have had the dog out fishing a bunch of times throughout stages in the build progress. Before we made significant gearing changes for the better it was able to pull around 550 to 600 lbs on hardpack snow and trail. Two 200lb men, 90lb flip hut loaded with auger and gear for the day.
I have been able to break trail through 1' of fresh snow in a field just bombing around up and down hills towing only myself. Joyriding is fun behind this thing.
There is a learning curve to be able to drive this guy on varying terrain. Leaning the machine to one side to turn in powder is different from pushing the handle bars left or right to turn on hardpack or ice. Riding on ice is actually quite boring as it is slow and perfectly flat a lot of the time. Pretty much anyone can get in and go straight on the ice. However there is nothing wrong with being able to tow all of your stuff out and be bored while doing it. Better than walking all day everyday just enjoy the scenery.