Ski Doo FormulaS 380 Worth turning into a Boondocker?

Not very many of those around in this part of the country. A buddy of mine rented one for his gf and she had a ball on it. We were running mostly groomed trails so she kept up fine. She wasn't very big so that was plenty of sled for her. I think it had the electric reverse which was a cool feature as well for the time.

If you can get the steering angle figured out I think the rest of it would fall into place. I'm not sure I would get too excited for the seat upgrade until the kid has enough inseam to justify a taller narrower seat. Upholstery shop should be able to help you out real easy. Or watch for a seat/tank from a Rev at a swap meet.

I've got a 340 Polaris and I put a 136x1.25 on it last year and was pleasantly surprised where it would pack my kid and myself on it (300# combined weight).

If I did anything to it at all I would just go with a 1.5 inch 121. Let him ride it a year or 2 and find a REV 550 summit for him. A 16 year old sled is not worth dumping a bunch of money into it. If I remember right the 380 was a single carb motor, surely wouldn't have enough power up high to turn the track worth a darn

I picked up gears for mine in my spare parts bin. I went as deep as I could go since it won't have the power on the top end to really wind out with that much lug. I left the clutching alone and it was actually pretty fun in knee deep powder. I think it would handle more, but that is all we had that day.

I picked my track up for $95 and a rear bumper with covers for another $15. I had the rail and tunnel extension so that part was free to me.

Good luck.

video

This sounds interesting. I look forward to seeing some video in the winter.

Cool project. I'd love to see the finished product. It should be a sweet ride with 50# kid on it.

When I had the long track skid out from under the 340 and the SnoScoot I popped the side covers off the bearings and pushed some grease in. I did clean them up first and made sure they rolled good otherwise they would get replaced. Apparently I put more grease than they would hold at speed according to the sling marks.

How heavy is the pilot?

I think you would be fine with your current gearing.

My thought is that the engine won't typically have enough power to fully spin that track like a larger engine would so it just needs enough power to pick the track up in the back and lay it down in the front so it can drive over it again.

:camera:!!

We did something similar years ago. We ended up with 17/44 gears. With a rider that small, and +/- 40hp, you'll never have a problem with a 17t top. Just make sure you use a chain that is proper for it. Doglegs are the Archilles Heel for chain longevity.

We actually found a tank and seat from a MXZX S-Chassis race sleds. The tank and seat aren't as big and bulky as the stock ones usually found on the S-Chassis sleds. This helped the rider move up closer to the handlebars quite a bit. (I know it doesn't look like a problem, but the fact that the seat and tank on the stock sled are so high up, when riding, it's actually quite hard for kids to ride that far forward. They 'highside' quite easily)

As for the seat, narrower is definitely better for small kids, I built my own seat for it using closed cell foam sheets, however I've seen guys hollow out the stock seat and replace the guts with pool noodles, then re-upholestered tighter to make it look like the seat has been narrowed. The back hump was also cut off but rear storage compartment was kept. 8" bridge and tapered down was just about perfect for my little brother when he was that age/weight.

Another cool trick is to mount a platform on the running boards to give your little guy some leverage. That's the biggest problem with kids and trying to maneuver full sized sleds.

Narrow ski stance is always a good start, glad to see you've addressed that.

And a mountain bar, however useless for most adults, helps the small people out tremendously until they figure out how to throw their weight and use the throttle to get the sled to go where they want. Also, I'm not positive on the throttle, but upgrading to a dual-stage throttle helps kids a ton as well. Either that, or a A/C style lever from the same vintage as they are longer and flatter.

Also, the biggest performance gain is a new belt. The belts for these things are very soft and wear out quickly. However because of their intended function, nobody really notices a lack of performance because....they aren't performance sleds. But fresh belts help tremendously.

When it comes to the steering angle etc, you can move the fuel tank and seat forward quite a bit if I remember correctly. Moving the steering to a more vertical position. Also, narrow handlebars help lots as well. Not ridiculously narrow, but narrow enough where you're young'un can stand on one side and be comfortable reaching over for the throttle. It's damn near impossible to learn how to handle a sled when your weight is off center because your bars are too wide.

Have fun! These things were severely underpowered, but a quick 550f motor swap and it's a whole new sled once your kid is ready for it.

That sled I described was for a customer/friend's kid. We did something similar to my old '99 Snopro 440f for my little brother. He rode it like this for a few years. Had a 121x2 BigHorn track and 17/43 gearing. Absolute RIOT to ride! This particular picture was taken on the trail up to Turtle Mtn in Revy where a group of guys honestly thought we choppered the sled into the riding area cuz they didn't believe that sled, with my little bro riding it, could make it that far into the backcountry.

Here are the platforms for the runningboards I was thinking of. Most kids that race sleds use these until they gain some height. You can kind of see the stock edge versus the platform itself.

And of the seat/tank combo I was talking about as well.

A new bar set-up can nickel and dime you for sure. However RSI has some cost friendly bars and everything can be purchased thru them if you end up going that route.

Hydraulic brakes would be ideal for your boy. I'm guessing it has the old mechanical style?
Salvage yard has to have something you can use....as for the throttle, perfect!

And a note about the brake, now that I think of it. I was always told never to use my brake. If I was following too close or going into a corner too hot....that was my fault and I shouldn't have brakes to fix my lack of thinking. Tough dad eh?

He did have to drag me out of the willows and ditches more than a few times, but all in all, I think I'm better for it now.

It basically showed me to anticipate much more than the usual guy, and get ready and setup for hair-raising situations. Besides all of that, it taught me never to touch the brakes while going downhill. (More advanced maneuvers/hills that do require the brake - not withstanding)

When I did use the brake I literally just wrapped my whole hand around it and pulled. Again, this helped me to rely less on the brakes and more on technique and anticipating. This was a STRESSED part about teaching my little brother the basics of sledding, and specifically mountain riding. Because he had a shorty lever with Cat Wilwoods, he was on them all the time. It took more than a few creative measures to stop him from using them constantly.

Can't wait to see this little rocket you're building!