Cold Weather Jetting Help. - Yamaha YFZ450 Forum : YFZ450, YFZ450R, YFZ450X Forums

YFZia505 · 12-04-2010, 04:02 PM

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.

1fast06yfz · 12-04-2010, 05:27 PM

in the winter i just turn in my fuel screw a half a turn in

12-04-2010, 04:02 PM	#1 (permalink)
YFZia505 Junior Member 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 04:14 PM.

12-04-2010, 05:27 PM	#2 (permalink)
1fast06yfz Senior Member Join Date: Jul 2009 Location: McCallsburg, Iowa Posts: 1,429	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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