winter jetting of a 400ex

[petralph]

has anyone had any experience with a jetted 400ex in the winter? I'm running a dynojet kit at 2400ft elevation, in 14 to 35 degree (F) ambient air temp, and a K&N filter. Fuel needle is set at the 3rd notch, with the fuel mixture screw at 3 turns open. There is a noticable drop in power when in 2nd and 3rd gear. Should I adjust the fuel mixture screw to provide more air to compensate for the cooler temperatures?

[Steve-o 400EX]

R u losing any performance out of ur machine? I live in PA and I didnt rejet for winter an my machine runs just as strong now as it did when it was warmer out. If it is runnin a little off. try playin with the air/fuel screw a little.

[jb400exxx]

mines jetted and it seems the colder it gets the more power it seems to have. just remember what your jetting is now, and mess around. if you screw it up to bad just go back to what you have now.

[Steve-o 400EX]

Originally posted by jb400exxx
mines jetted and it seems the colder it gets the more power it seems to have. just remember what your jetting is now, and mess around. if you screw it up to bad just go back to what you have now.

Great point JB, Mine seems to run stronger in the winter too. But I think it has to be close to begin with to notice this. JMO.