ANOTHER SLED PROJECT... SPRINTFIRE #2

[SS440-80]

Summer... The right season to buy sleds.
So I went for a little trip and got another John Deere

Guess what model??

[TASKY]

Its either an 82 Sprint/Snow fire with the right fuel tank or a 83-84 Sprint/Snow fire with a Spitfire fuel tank and a track for a direct drive Polaris. Jag Vinst!!!

[SS440-80]

Its either an 82 Sprint/Snow fire with the right fuel tank or a 83-84 Sprint/Snow fire with a Spitfire fuel tank and a track for a direct drive Polaris. Jag Vinst!!!

Du vinner!
It's a 1983 Sprintfire with a Spitfire fuel tank and the track I really don't know yet what sled it's supposed to fit. Haven't had time to check.

Here comes a few more pics of the sled. The guy I bought it from used the things he had in his garage to make the sled rideable....
Sadly, there are Spitfire pistons in the engine. But fortunately the engine has not been run more than a few hours whit them, so I hope that there are no damage there.



Nice Yamaha seat???






Pipe from a Ski-Doo 380, don't know witch model.




The aluminium frame has been welded. Solid good work.


I think that the drives has been changed.

[TASKY]

Track is a 80's plus Liquifire replacement with 3.29 pitch drivers.

[nick80lf]

Whoa.....Bet that has a high drive ratio.

Sent from my HTC One_M8 using Tapatalk

[SS440-80]

Now it's two year since I bought my Sprintfire #2, and it's time to do some fixing up

The sled has been parked in a shed until now, I have only taken the skies of it and mounted on my Sprintfire #1.

As you saw on the first pics the sled has gotten some non-original parts like seat, gas tank, exhaust, track, driveshaft and sprockets, primary clutch, pistons and of course the really ugly color.
But I have tracked down the seat and gas tank from previous owners, and I don't think that the driveshaft + sprockets and the track is bad.

So placed in the sled lift, the parts coming off.
I'm gonna take everything apart, clean and repair and mount some new parts.

[SS440-80]

A picture of the exhaust pipe

[SS440-80]

The driveshaft bearings do not look good, so they must be replaced.

Skid pulled out. It still has the original shock.


I wonder what the guy who mounted the limiter straps where thinking, they sure does not stop the shock from hitting the maximum length



The secondary is in better shape than the one on my Sprintfire #1



No speedometer drive, but a home repaired brake disc with a odd woodruff key


Very home made brake disc...





Driveshaft is free in both ends

[SS440-80]

Engine is out and will get a overhaul in the autumn

[SS440-80]

Now the track and driveshaft is out...

But now I'm really beginning to think a lot about the drive ratio with the Liquifire 12T drive sprockets with 3,29" pitch VS the original Sprintfire 8T sprockets with 2" pitch?
I do not know the diameter on the 8T sprocket, my other Sprintfire has 7T and it's somewhere around 4,5" and the Liquifire sprocket is 6,1".

And after reading about the TRACK INTERCHANGE INFO in this thread http://www.jdsleds.com/community/viewto ... 4&t=93/url I am worried that the ratio will be too tough for my little Sprintfires clutches? Or will the setup work alright?

Would it be better to rebuild the skid to fit a 121"x15" with 2,52" pitch, and change the sprockets to smaller ones?

I could also go a different way and work on the cylinder ports to get more power at a higher rpm, use a dual carb setup and build two tuned pipes. And with a more powerful engine change the clutch setups to pull better with the higher drive ratio. Much work of course, but I do not want to have a weak sled with just a high top speed.

Help me with some good advise about this, please.

[SS440-80]

With most parts taken off, it's time for a good cleaning with a high pressure cleaner.
Much nicer to work on the sled without all the beltdust and old oil







Ready for a high pressure wash with hot water.




Pretty big difference I think

[JoeRainville]

Robert,

Glad to see you bringing another Sprintfire back to life. Unfortunately, the correct drive sprocket does not yet exist to adapt the 3.29 inch drive lug pitch Liquifire track properly to a Sprintfire "direct drive" set up. The larger diameter track drive sprocket makes for a very tall gear ratio, like trying to start your car in 2nd or 3rd gear, while on a hill. It would result in a lot of belt slip...unless you can find a larger diameter driven clutch (like one from a newer Arctic Cat Bearcat perhaps) to return the gear ratio closer to original.

I have been meaning to get a few sets of small diameter, 3.29" sprockets machined up for my own Sprint and Snowfires, but have yet to do so...

-Joe Rainville

PS: I have a ton of NOS (new old stock) speedometer drives, cables and such if you need them sent across the pond.

[SS440-80]

Thanks for the info Joe

Now I feel that I have to figure out what will the best way to go.
I don't think that a Bearcat clutch will be a good option. Because if I increase the diameter on the driven clutch I also have to get a primary clutch with larger sheaves. The P85 might work, but it does not look good right now.

A easier way is to rebuild the skid and use a 2,52" pitch track from a Yamaha SS440, GP440 or a early SRV with a 116" length. I believe that the smallest drive sprockets that will fit is 7 tooth.

Or I will take the time and make me a pair of 3,29" sprockets with a diameter somewhere near 4,5-5 inch...

It's good to know that you still have some JD stuff and are willing to ship to Sweden

[SS440-80]

When the previous owner converted the drive and track, he had too mount the skid almost 7cm more forward in the tunnel due to the drive sprocket size.

He put reinforced mounts for the skid.


The screws was a bit long...


I put new carriage bolt in with the exact length, so it looks a bit better. But when/if I can solve the drive sprocket size problem, I will mount the skid in the right holes.

[SS440-80]

Got some new parts today, so now the project can go on...




So I took the secondary apart and sanded off the rust and painted.