Do you need new jetting on '07 YZ450

Trying to decide on a new '07 mxer (riding an '05 WR450 now). I'm wondering if the YZ needs to be rejetted for the eaerly Spring New Engalnd weather (races start in March when its in low 30's).

Is it fine to leave it alone? (my WR hesitates and coughs off idle).

FYI I am a 40 year old vet novice.

Any comments (besides that I'm an old fart)?

Trying to decide on a new '07 mxer (riding an '05 WR450 now). I'm wondering if the YZ needs to be rejetted for the eaerly Spring New Engalnd weather (races start in March when its in low 30's).

Is it fine to leave it alone? (my WR hesitates and coughs off idle).

FYI I am a 40 year old vet novice.

Any comments (besides that I'm an old fart)?

Check this out, I'm doing it next week.

ZipTy Racing Carb Modification

Looks awesome!

But for colder weather riding, is the stock jetting OK or is it a must-do mod until the warmer weather gets here? If so, what size jets would be best?

Looks awesome!

But for colder weather riding, is the stock jetting OK or is it a must-do mod until the warmer weather gets here? If so, what size jets would be best?

Seems like it should be jetted for your location. Ride it and see how it runs.

Install the optional 165 main and turn the fuel screw out 1/2 turn. You may even want to go to a 168 or 170 if stays cold all day.

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