jetting for new weather conditions

[sick 96 250]

I have been doing a few searches about jetting for when it gets cold out. Some posts say that you have to lean the bike out more because the cold air will richen the jets and others say the opposite. This is the one thing i keep forgetting when it comes to jettings, is which way to jet when the temps change. Also when you move up or down on the needle a clip, what is the size equivilance for the pilot jet ( how many sizes does does it change on the pilot)? :eek:
Thanx

 

[dirt bike dave]

A given volume of cold, dry air will have more oxygen than the same volume of warm, moist air. When you have more oxygen, you need more fuel. So richen your jetting for cold weather.

Pilot jet and the needle are totally separate. They may have some overlap in the rpm range that they inluence, but I don't think you can make any blanket statments about how how one pilot size is the same as changing the clip by one or two grooves.

 

[biglou]

Three H's: Height (altitude), Heat and Humidity. As these go up, you want to jet leaner, and vice-versa. So, colder = richer. Don't know how to relate the needle-pilot relationship. I thought they handled slighly different parts of the throttle range, like 0-1/4 and 1/4-1/2, respectively.

 

[sick 96 250]

ok so i need to jet richer for cold weather, got it. I have extra jets for that but i just wasn't sure about if moving the clip would help out. In my manual on the diagram the pilot and needle mainly cause the same effect in the rpm range so i figured it was along the same lines