yfz450 jetting

[Autobot]

my buddie has an 05 yfz 450 and would like a jetting chart if someone has one, or if any of you have an idea of what to run. here is the information, alt. 1200ft. temperature about 5* or 10* has aftermarket exhaust. any help would be appreciated

thanks

[GMouldy]

The truth is in the color of the plug my son



Best way to see where your jetting is in a ballpark is to pull the plug.

If the tips black and oily, your rich,
if the tips grey and dry, your lean,
if the tips a light brownish, your right on the money.

Its just something your going to have to play with. Pull the plug, clean it off ride it for a while, pull it back in, pull the plug to see the color, and repeat.

if its a stock bore bike with no major engine work, i'd just swap out the main jets.

another way of getting your jetting spot on is to take it to a Dyno and do numberous pulls.

[J.R._Hinds]

screw it just run it wide open never lift always works for me