jetting

[dirtbikr99]

advise for grateful rider, hi i have a 02 cr 125 and the jetting is way off on my bike due to major modifications on my bike, i do most of the work on my bike but i suck at jetting so i brought my bike to a shop near by to get jetted, but all the sudden it got cold again around 32 f well if it gets jetted for that weather when the weather gets good again around 75 f will the jetting not be correct or as good as it was before???? please shed some light on this

 

[RM_guy]

The warmer it gets, the less dense the air (therefore less oxygen) so you'll need to lean the jetting. As it gets colder the air is more dense (more oxygen)and you need to richen the jetting. You have to be very careful riding when it's cold out because you can seize the engine unless it is re-jetted for the colder temp.