ice/grass mods

[abartolotta]

I have a 96 polaris ultra 680, I would like modify it (on low budget) to ice drags and possibly some sod drags,what carbs do I need to transfer to 110 or 140 octane race fuel, or what other mods can I do to perform better/faster.
The sled has triple pipes, some sprocket gear box changes, running picks in track, rest is stock..

 

[mike_s]

Lots of things you can do to an ultra. Port work, reeds, heads, big bore, I had mine out to 862 cc. They are still impressive today with the right mods.

Who's pipes do you have on it now?

Sent From God Knows Where...

 

[abartolotta]

This may be a 'Dumb question'--can I use the 680 block & crank with an 800 top end(sleeve,pistons,rings)? Will it work,giving more power to it or is it not worth it?

 

[LoudHandle]

This may be a 'Dumb question'--can I use the 680 block & crank with an 800 top end(sleeve,pistons,rings)? Will it work,giving more power to it or is it not worth it?

I have a complete triple '96 600 SE big bored to 800 complete with Crank Shop triple pipes, Hot To Go ported 800 cylinders, Union Bay Racing domes, Bored TMX flat slides. Rated about 210 HP for sale see signature. I'll let it go for a little over shipping costs, make me an offer. I bought from Troy Pierce back when Polaris was supposed to sponsor him in the asphalt drags, they pulled sponsorship and he sold off the parts. Tried to use it twice for the Alcan 200 road race, but other issues interfered. Ran it once in a hill climb but the hill help interfered with my first run and the rest of the sled got damaged in the carnage. Engine is fine and run able if interested. I'm in Alaska.

I'll throw in the extra carbs and all the tuning parts as well. One spare piston and rings.

Same crank and cases as the ultra if I remember correctly. Let me know if your interested.

 

[mike_s]

This may be a 'Dumb question'--can I use the 680 block & crank with an 800 top end(sleeve,pistons,rings)? Will it work,giving more power to it or is it not worth it?

If i remember correctly, the crankcases are the same. Top ends should interchange. There are different ignition curves, the xcr 800 had a different timing curve for the triple pipes and hotter porting than the ultra with its single pipe and more docile porting.