gearing?

[Killa900_1m]

just got sled it has 19 top 41 bottom gears and i also have a 21 top and a 43 bottom ....... and one have a idea what stock is for a 900 159 or what i should be running, go most riding in western Maine. really dont want to see over 85 but i think the 19/41 is to aggressive?

 

[01ZRTCAT]

20/39 stock 0 to 3000ft
19/43 for elevation

 

[1Mike900]

If you are mostly riding flats and no altitude (below 2500ft) I would go with the 21/41 If higher than that go with what they installed! I would torque load the engine if possible and not let it run free at the lower altitude + it makes more power! 19/43 is for 3500 ft and above!

19/43 = 2.26 ratio
21/41 = 1.95 ratio
20/43 = 2.15 maybe best all around?
19/42 = 2.21
The 20 upper gear is more efficient, but for the most part not necessary unless you are doing extensive steep climbs!

Mike

 

[Killa900_1m]

http://www.turboaddictionparts.com/catalog/snowmobilecalculator.html


is this accurate? also have to check if i am running a 8 or 9 tooth

 

[Killa900_1m]

i do have a 9 tooth ratchet drivers and i do have a set of 20-42 gears will the chain that is on the 19-41 gears works?it is about 3/4 in on adjustment?..... no it wont guess try next size up on chain

 

[1Mike900]

The calculator is very close, just depends on the overdrive of the secondary clutch? A stock '04 900 EFI ran 82 mph. on a snow west test, followed by the KK at 80+. Seems like the stock 72 pitch chain would work! The 74p. 20/46 is a perfect pitch meaning it just wraps around with basically no adjuster tension. Most efficient! Mike

 

[1Mike900]

72 p. chain should be almost identical as a 19/43 setup! 20/42 is just a hair shorter chain lg. Can you measure the ctr/ctr distance of the shafts? I am thinking they are 7.50" apart? Thanks Mike