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Old 01-07-2013, 09:11 PM   #1
2001kx
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Default ultra 680 clutching / gearing question

96 ultra sp 680 single pipe

i have just ordered a set of gears 20 / 39 1.95 ratio.
is this too much gear?(i dont have them yet to test)
i dont do much open riding...mainly tighter / hilly areas.

will i have to change the weights on my clutch?
right now it is all stock.

my sled is sluggish on the take off but from mid on up its not too bad.
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Old 01-07-2013, 09:31 PM   #2
meburdick
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20/39 was the stock gearing for the Ultra RMK.

Did you order a new chain, too? You likely have a 64W chain and will need a 66W to accommodate those gears.

Personally, I think you're going about this the wrong way... I would never start with changing the gearing because takeoff is sluggish. IMHO, you should be looking at the carbs, clutches, and belt long before you open the chain case.
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Old 01-08-2013, 01:27 PM   #3
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20/39 was the stock gearing for the Ultra RMK.

Did you order a new chain, too? You likely have a 64W chain and will need a 66W to accommodate those gears.

Personally, I think you're going about this the wrong way... I would never start with changing the gearing because takeoff is sluggish. IMHO, you should be looking at the carbs, clutches, and belt long before you open the chain case.
well changing the gearing was cheap (19.99) so i thought i would give it a shot....Its not hard to change back if i dont like it.
if the chain isnt long enough i may just use the top (small ) gear to give me a 1.75 ratio...stock is 1.66
i am in the process of cleaning my carbs and seeing what i have for jetting...i will report back with my findings if i can get some jetting help as well.
when it comes to clutching it seems you need a engineering degree to figure out what you need -lol
the sled was $800 and i only rode 1 time last year in 5" of snow (thats the most we had last year on the ground) so im not really into putting lot of money into this thing.
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Old 01-08-2013, 02:03 PM   #4
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You can use the top gear and still be ok with the 64W chain - it's definitely the bottom one that forces the need for the larger chain.

For jetting, your stock settings would be:
340 mains, 50 pilots, air screw out one turn. Those would be appropriate for 0-20 degrees at up to about 3000 feet elevation.

Other temps / elevations would require different jets.
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Old 01-08-2013, 02:04 PM   #5
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For the clutching part... what's the engagement RPM? All of my sleds have always grabbed at 4200-4700 range, and that's generally about where they should be. If you ride different elevations, you may need to changes weights. But, changing the jetting shouldn't require it.
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Old 01-08-2013, 02:12 PM   #6
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Quote:
Originally Posted by meburdick View Post
You can use the top gear and still be ok with the 64W chain - it's definitely the bottom one that forces the need for the larger chain.

For jetting, your stock settings would be:
340 mains, 50 pilots, air screw out one turn. Those would be appropriate for 0-20 degrees at up to about 3000 feet elevation.

Other temps / elevations would require different jets.
elevation here is 1200' and temp usually in the 20's
right now the colder it gets the better it seems to run..
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Old 01-08-2013, 02:15 PM   #7
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Originally Posted by meburdick View Post
For the clutching part... what's the engagement RPM? All of my sleds have always grabbed at 4200-4700 range, and that's generally about where they should be. If you ride different elevations, you may need to changes weights. But, changing the jetting shouldn't require it.
i cant remember what it engages at right now but will check once its running again (few days)
also i heard that its ok to run ATF in the gear case?

i was running 80w gear oil..
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Old 01-08-2013, 02:28 PM   #8
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For me, it's just as simple to put in the Polaris SCL (Synthetic Chain Lube). A bottle of it costs about $15 and I've already done two chain case oil changes with it and have some left (Poo claims 9oz, but you'll never use anywhere near that if you go by the dipstick).
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Old 01-08-2013, 02:29 PM   #9
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Quote:
Originally Posted by 2001kx View Post
elevation here is 1200' and temp usually in the 20's
right now the colder it gets the better it seems to run..
And once the temp drops to the teens, it should be fantastic with that stock jetting (that's about what it's set up for). Right now, with the warmer air, you're running a little rich. Don't tinker with it, though, because you don't want to end up lean when the temps drop.
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Old 01-08-2013, 02:46 PM   #10
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And once the temp drops to the teens, it should be fantastic with that stock jetting (that's about what it's set up for). Right now, with the warmer air, you're running a little rich. Don't tinker with it, though, because you don't want to end up lean when the temps drop.
ok sounds good...i will just clean the carbs and check to be sure i have the stock jetting...
It can be a little hard to start once warm and i will need to give it a little gas for it to start...hoping its just dirty carbs...we'll see.
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