• Don't miss out on all the fun! Register on our forums to post and have added features! Membership levels include a FREE membership tier.

96’ ultra sp 680 gearing questions.

R
Feb 9, 2018
23
2
3
32
La Pine
96’ ultra sp 680 gearing questions.

Have a 96’ ultra sp 680 that I’m trying to dial in. I Am jetted for my elevation (5000-10000) properly clutched also forgot my weight right now have been switching to much for setup (8200 max rpm) have been playing with Polaris blue and arctic cat yellow/green seeing what is working better. Cat gives a higher engagement but also bogs slightly under 10mph and the Polaris engagement is a little lower with less bog but still low on power under 10 mph which makes for poor off trail riding. Sled has a big wheel kit and a 136”x1.5” track with an 8 tooth driver and currently has 21T 35B for gearing which is where I think my problem is. Was running a 20T 35B which was slightly better but not much.

This was someone else’s mod sled back in the day that I picked up super cheap because it needed a rebuild and I had a fresh bottom end laying around. So the sled has a freshly trued crank with fresh top end. Clutch was fully rebuilt also at the time with all new roller, bushings, and springs also shimmed for new belt clearances.

Any input greatly appreciated, will be playing with different gearing setups a few times a week due to having about any gear setup available.

Thanks for your time everyone.
 

ultra800

New member
Premium Member
Jan 26, 2008
48
4
8
Gearing

Put a 39 on the bottom! Have the clutch shimmed too .015- .020 gap between the belt. sink the carbs
 
Last edited:
R
Feb 9, 2018
23
2
3
32
La Pine
carbs have been synced, belt clearance was shimmed to .015 during rebuild. have the chain case apart now and hunting for a 39 bottom in our box of gears here.

Thanks for the reply i will let you know how the 39 bottom works out should be going out again this evening for a ride and testing. having snow at the house would make this much easier.
 
R
Feb 9, 2018
23
2
3
32
La Pine
Couldn’t find a 39 bottom. Ended up inspecting secondary and found the spring not into its retainer spot of the sheave not the helix. Had excessive casting markings preventing the spring from seating fully in its whole. Cleaned the clutch inspected buttons put together. Also found a Polaris red primary that I tested out. Engagement was much better and max rpm is right. I did a sharpy test mark in the clutch to see how high the belt is riding to see if I could Change gearing anymore and the belt is running about .5” from the top of the clutch so limited in my gearing options but am happy with the set up. Great low end now and 80mph top end which is fast enough as I use it as a mtn sled.
Thanks for the input to all.
 

sno*jet

Well-known member
Premium Member
Dec 13, 2007
2,820
1,283
113
why the 8 tooth drivers? what pipes are on it?
i would put in 9 tooths or swap in a 2" paddle and 19/39 gears since its used for mtn riding.
 
R
Feb 9, 2018
23
2
3
32
La Pine
Stock pipes, in my experience the 9 tooth driver on a larger lug track will hit the bulkhead. This is just a back up spare sled so keeping budget low. Will take a set of 19-39 and try them. Am almost happy enough with it to leave it but will try that gear setup and see how it goes and let you know. Going to ride Sunday so will let you know Sunday evening.

Thank you for your input.
 

sno*jet

Well-known member
Premium Member
Dec 13, 2007
2,820
1,283
113
Stock pipes, in my experience the 9 tooth driver on a larger lug track will hit the bulkhead. This is just a back up spare sled so keeping budget low. Will take a set of 19-39 and try them. Am almost happy enough with it to leave it but will try that gear setup and see how it goes and let you know. Going to ride Sunday so will let you know Sunday evening.

Thank you for your input.

so its a single pipe then on an sp i believe.
ive had an sks and rmk '96, both fit 1.5 with 9 tooths easy, maybe sp has a large bulkhead cooler? what track do you have exactly
 
Premium Features