Cold Weather Jetting Help. - Yamaha YFZ450 Forum : YFZ450, YFZ450R, YFZ450X Forums
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post #1 of 2 (permalink) Old 12-04-2010, 05:02 PM Thread Starter
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Join Date: Sep 2010
Posts: 10
Cold Weather Jetting Help.

Whats up everyone. so over the summer i had to re jet my 07 YFZ due to elevation change. im at about 5000ft + above sea level(New Mexico). it is jetted for 90 degree weather and now it is down to about 35-40 degrees. i have a 158 main, 42 pilot, needle on the 3rd from top and screw is just over 1 1/2 turns out. it does seem to be running a bit leaner. any suggestions on where to start tweeking these jets? Any help would be appreciated
i did seach some other threads and none of them really helped my situation.

07 YFZ450
Grey on Red

Last edited by YFZia505; 12-04-2010 at 05:14 PM.
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post #2 of 2 (permalink) Old 12-04-2010, 06:27 PM
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Join Date: Jul 2009
Location: McCallsburg, Iowa
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in the winter i just turn in my fuel screw a half a turn in

06 yfz450-Gibson-PEP ZPS
stroker sb 13.75 cp ported head
Hot cams Intake and stock exhaust
Rossier exhaust
Sredrum 42.5mm carb
FCI Jetting 175m 45p 3 1/2th clip 2 turns
Kick start
Team Fat Boy Racing
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