Cold weather,jetting changes

[adriano.ro]

Temperatures drops,we need to rich up the mixture,so what do you prefer to change pilot jet,needle position,or simply close AS?

My set up is: 42 N3CG#3 180. As 1.5( bike run perfect)

[Brian VT]

I just raise the needle 1 notch. Works for me.

[shang]

I usually just move the needle up a clip as well. I'm running pretty fat right now so I may just leave it. I don't usually ride anything less than 30 degrees anyway.

[chrille79]

I live in Sweden and it can be minus 20 here, i just turn the air screw in little and block one cooler. I drive all days the piston is now 100 hours and no problem so far..Maybe if you run at high revs most of all time you have to change needle clip pilot jet.

[Brian VT]

Originally Posted by chrille79

....Maybe if you run at high revs most of all time you have to change needle clip...

I don't normally ride in the upper revs but snow riding tends to bring them up fairly often. That's why I raise the needle.
Also, deeper snow means slow riding (= hot coolant) so more fuel = cooler engine.

[Zman]

It all depends on the amount of temperature change. If you are jetted correctly for one temperature and are planning to ride in a 40F cooler temperature I would richen the pilot, needle and main jets.

[Jakobi]

As per Zman.

Good up correction factor chart. You'll find a table where you can determine the factor based on temp and elevation.

Then go something along these lines.