Jetting

[Architects]

Who rejets for the winter. Its about 27 degress right now and I might be going riding later tonight in the snow we got.


Currenlty it has a 180 MJ
50 Pilot Jet
A/f 2 screws out.


How lean am I going to be or will I be ok?

[GPracer2500]

All else being equal, every 25 deg F is usually about 1 jet size (e.g. 180 to 182). Sometimes 1 size for every 20 deg works out better because the humidity in the air tends to go up and down with temperature.

Winter = cold and dry = lots of oxygen in each unit of air.
Summer = hot and humid = less oxygen in each unit of air.

There's a "How To" on finding the best pilot jet and fuel screw setting. If you don't want to go through that procedure then backing out your fuel screw 1/2 to 1 turn is probably a safe bet.

If you know for sure that your jetting was correct for summer temps then it's fairly accurate to rejet based soley on temp/humidity/elevation changes. If your only pretty sure your jetting was spot-on then go ahead and make changes for conditions--but don't assume what you've done is correct. Be sure to test the results of your changes. What I'm getting at is that if you maybe where a little fat in the summer then you might be pretty close to correct right now.

[Architects]

To be honest I jetted it in the summer. Frame cracked and had it torn down to get frame replaced. I had maybe 5 minutes in the summer on current jetting. I did practice once in 55 degree weather and it ran real strong. No popping on decel. No bogs or misses. Curious to see how it runs in 25 degree weather. I have a 185 MJ I can toss in if all else fails


Mods=

Nmotion full exhaust
Cut airbox lid