yamahaboy701
New member
I am taking a trip out west this year with my viper. The elevation of cabin we are staying at is 10,000 feet. My viper is a 2002 with a completely stock motor (jetting, exhaust, etc); according to the yamaha fiche the main jet stock is 156.3 and the pilot is 45. I have a 136x2" track on it with stock gearing (22-38 ) and 8 tooth drivers. What will need to be done for clutching and for jetting?
Last edited:
yamahaboy701
New member
How about just the jetting?
Stock motor - no mods?? Should be able to jet it right off the chart and be pretty darn close. Same with the clutching. Generally at elevation you're going to have to increase the pilots, lean the mains and needles, lighten the weights, and tighten the secondary. Have you been to snowet.com?? All things mountain are discussed there. I have no experience on a viper so I can't give you any setups other than a best guess which might work, or might burn you down:-)
mopar1rules
Active member
Ryan B said:
yamahaboy701
New member
Maybe I will check out sno west. But if I am reading the tech charts right here on totallyamaha, it list the same main jet and pilot jet for both the mountain viper and trail viper. How can this be?
mopar1rules
Active member
that's for sea level elevation. you will need to look in that service manual i sent you for the jetting at 10,000 feet above sea level. the clutching for that altitude is in there as well.
That's the one. Darn fingers. Can't type at all 
mopar1rules
Active member
that's the one what?
yamahaboy701
New member
Thanks guy!
Jetting for -20F at 8000-10000ft
MJ#145 PJ:#55 JN:3 1/8 PS:2.0
That was too easy
Jetting for -20F at 8000-10000ft
MJ#145 PJ:#55 JN:3 1/8 PS:2.0
That was too easy
mopar1rules said:
snowest.