as the temp continues to drop here I am wondering is there really any reason to change the jetting on my 07 WR450. So far it has only reached down to the upper teens F. It still starts as well as can be expected with a small old battery. I have not had to kick it yet but do need the choke( enrichner? )which I have no use for during the warmer months. It seem to run stronger when it is cold. I am just afraid that the extra power is from it leaning out. I will still be riding in to the single digits and perhaps the high negatives F. I have always done this on my larger multi cyl 4 stroke road bikes.but they have easy access to plugs and carbs.