Could someone please clarify the following?

Jet smaller for sea level, jet larger for higher altitude?

Jet smaller for warmer temperatures, jet larger for cooler weather?

Are these basically good rules to follow when jetting a 4 stroke such as a Raptor?

Thanks!

 

Anyone?

 

i think you have it exactly opposite.

you would jet larger for either lower altitude or colder temperatures as both make the air more dense..therefore you need more fuel present to make the combustion happen correctly. the reverse is true too. the higher you are or the hotter the ambient air temperature is, the less dense the air is, therefore, you need less fuel in the mixture.

 

roughly one jet size smaller for each 2000' or so in elevation
roughly one jet size for each 30 degree change in temp
colder you go richer, lower elevations you go richer
warmer you go leaner, more elevation you go leaner

Dennis kirk has a mikuni carb tuner that is on a sliding scale, you put in your main jet size, & see what effect elevation & temp change has on it.. it is worth the 3 bucks they ask for it.