Super Powered Sportie

[O'Deere]

Finally got w/ another snowmobile guy & his room to roam back fields. My man came from a 575(?) Polaris earlier in the season & was beyond impressed w/ the power of the 440 Sportie. Said the Sportie would walk all over the much newer & heavier Polaris. He could run full throttle for long stints in his backfield w/ the Polaris but couldn't apply full throttle for more a few seconds on the Sportie w/o feeling he was going to be throwed or the thing was going out of control.
I thot my Sportie felt awfully powerful for just being a 440. Don't know if the fella that rebuilt her that I bought her from might have bored her out? Just gobs & gobs of power. Even at high speed if you open the throttle more it will often spin the track.

[guitardude081]

Keeping in mind that there wasn't much track lug under sleds of this era, spinning is easy to do. The Sportfire was light and agressively tuned. It was quick for a single carb 440 fan and in my opinion is just as fast as Polaris' newer XCF 440s. Always remember that there is NOTHING slow about a 440. You can tune a modern 440 to run right next to or ahead of an 800 without much effort or $$. The only downfall to a tuned 440 is that if they run constantly at high speeds, they need to be re-ringed more often than their big bore cousins. 440 has always been my favorite number in the snowmobile world.
~Jack

[JD_Sledder68]

440 Deere's and 440 Mopars.....I love em both! If Deere would have made a Hemi sled, I'd have one of those too.

[moontree]

440 Deere's and 440 Mopars.....I love em both! If Deere would have made a Hemi sled, I'd have one of those too.

that sounds like a good challenge

[JD_Sledder68]

Hmmmm...Now that I think about it....I have a

- 340 Liquifire and Cuda 340
- 440 Trailfire and 440 Dart Sport

[manitobatrailfires]

Someone else started this Dodge talk, not me.
Which sled chassis can we fit a Cummins into?
I think it better be a wide track with some fat skis.

[O'Deere]

Anybody speed check their speedometer? Been reading snowmo speedos might run 20 MPH fast.

[O'Deere]

I have a 4 year old non powerjet VM-34 Mikuni on the Sportie. I'm finding I've got to set it up w/ a smaller main jet than the book specifies. W/ the 200 main & the needle set at the 3rd notch the sparkies are showing almost black. Stuck a 190 main jet in there which the book specifies for above 4000'. Will see what that gives me.
Wonder if the non power jet version of this carb reqires leaner jetting?

[O'Deere]

Hmm I wonder about that screen in the air intake tube? Should check that.

[O'Deere]

So much power. Have pulled the track drive shaft out of its bearing flange on the speedo transducer side. Ahhh. Couldn't get the track to stop ratcheting even after tightening track & then the shaft pulled out. Wonder if theres something wrong in the chaincase.

[JDT]

Maybe the racheting was not the track but the drive chain?

Could be that the sprocket retaining bolt came loose.

[trailfire runner]

My 440 trailfire did the same thing. got it home and opened up the chaincase the chain came off the sprockets

[tmartin]

Anybody speed check their speedometer? Been reading snowmo speedos might run 20 MPH fast.

My brother clocked my 80 trailfire 340 at 52 mph this weekend. This was on soft trail conditions at i was not maxxed out yet. He was running along side me with a 05 sabercat. I figure this is fairly accurate. The trailfire once it hits 40 on the guage it fluctuates so much that i cant get an accurate read but it was within 5 i would say. I know the mechanical drive speedos are off though 20 mph is a little more than believable. New ones with the speed sensors gps within a few mphs.

[O'Deere]

1 side of the center boggie wheel shaft was missing its bolt & the wheel on that side was hanging down. After fixing, the track still doesn't want to center on the rear boggie wheels. Pulls to 1 side. Something bent, maybe?

[JDT]

Did you do a proper track tension and alignment procedure?