Sled Rebuild

[crazycart]

This thread can be moved if a new section is created for other stuff.

So i have a 1989 Polaris sprint 340 snowmobile which i am in the process of rebuilding from the ground up as a summer project.I plan on sandblasting the whole bellypan/tunnel,and giving it a good paintjob.
I'm redoing the front suspension,and the rear,also converting it from a 116" track to a 121".The new-er track also has quite a few studs(steel carbide picks) which make it hook up good on ice etc...(WHEELIES)Im going to rebuild the engine(possibly overbore) shave the head,port the intake and exhaust,and rebuild the clutches.I will be mounting on twin SLP expansion pipes and MAYBE dual 38mm mikuni's(has 34's right now i think).

Hopefully ill have myself a good little sled to rip around on for fun this winter.This snowmobile is considered very small in the sled world,but i like it because it is very light and you can throw it around easy,i also have a 2005 polaris 550 twin and a heavily modified 1990 polaris 650 triple(which will exceed speeds of 100 mph).

Heres a few pics of it stripped down and the engine(broken piston skirt,but the cyls are in perfect condition)IUm still debating whether i should buy std. bore pistons or .40 overbore.Both kits are 30$ Im not sure how much its costs to get a bore job though..
Heres what it looked like before(crap lol)

 

[oscaryu1]

Nice! It doesn't really look that bad before, but what am I to say? It snows every 10-20 years here haha

Nice project though. 2 strokes I suppose?

 

[crazycart]

Yup 2 strokes

That was also and older pic of it,it looked alot worse recently,and it had a horrible bog,the steering was very clunky,rear suspension sucked,track was in horrible condition, it goes on and on lol,mostly performance was suffering.haha and i also was driving it and it backfired and caught on fire and melted a bunch of stuff
Heres what it looked like COMPLETELY stock,fugly aint it?

 

[ironman]

hey crazycart let me see a better picture of that carb. setup on there.looks like my 292 setup

 

[crazycart]

Okay,this isnt MY engine,buts its basicly the same thing except for the shroud on top.

 

[crazycart]

A little update.I first used a cold galvanizing compound( 93% zinc) which stops rust.I then primered,then used RustOleum Professional Flat Black.Turned out pretty nice for spray paint.(ran outa black lol,so its not done yet.)

 

[crazycart]

Finished painting.Also made a handlebar riser out of angle iron and square tubing.

 

[oscaryu1]

Gonna ride it on the streets ain'tcha?

 

[crazycart]

lol thatd be quite a ride on this thing.Ive done it before though

Check out this vid its just insane.
http://www.youtube.com/watch?v=FtXBm6VF_Zo

 

[crazycart]

I also do quite a bit of "water skipping" Who sais you need a jet ski for fun on the water?

 

[Kenny_McCormic]

LOL, be careful doing that.

 

[crazycart]

Ive actually ran out of gas while going over water,not a fun experience lol.

 

[gocartkid]

Ive actually ran out of gas while going over water,not a fun experience lol.

I hope you know how to swim!

 

[kibble]

Ive actually ran out of gas while going over water,not a fun experience lol.

LOL!

 

[ed1380]

Ive actually ran out of gas while going over water,not a fun experience lol.

 

[crazycart]

Well 2 weeks ago i dropped off the engine at a machine shop to get bored for the .40 over pistons, and i painted some suspension parts.This project has been goin kinda slow lol

 

[crazycart]

Got the cylinders back. 90 bucks for boring and honing. i cant wait to get this thing goin.
Wow what was the machinist smoking on? Thats a extremely good price for that work!

 

[Jerryburger]

I think the sled kicks _ss even stock! Is it the same kind of motor as "Ed's Black Terror Kart of Death" motor. (A 440cc twin aircooled.) If so... it's gonna fly without making a mark in the snow. I am a real fan of those Polaris/Fuji twins.

 

[crazycart]

Yeah its a 340 just newer model engine. Its rated at 38HP stock. Which really isn't that much in the sled world today. I have some twin expansion chambers im going to put on (they look BA!) and some dual Mikuni 36mm Carbs(stock is like 32) Its also bored out, and i got a newer clutch for it, newer clutches are a goodway to get all the power to the ground(or snow).We put a new secondary on our 1990 Polaris Indy 650 (Triple Cyl. Liquid cooled,triple pipes, lots done to engine) Its rated at about 120-130 HP, and that clutch made a huge difference in the holeshot. Hold it wide open and it'll keep the skis up as long as you want. Sorry for rambling on about this, but i love it lol...

 

[2or3wheels]

snowmobiles are so fun. Want to know a real sleeper snowmobile. Our 85 ski doo MX 470 LC. Some how, stock set up, keeps up and or passes my aunts 98 polaris 500 LC. Has not been re-built it in a long time. the primary has a odd noise but we feel if it aint broke dont fix it.

On another note how do you "summerize" or store your sleds? we always run seafoam or stai-bil through like 5 gallons and run the carbs completely dry. Us personally have never had any problems.