jets

[mikebrand]

I have a 2005 YFZ450, have a whitebrothers exhaust, aftermarket airfilter. Ran 178 jet-was lean. Ran 180 jet-was rich. Do I need to change pilot and or needle??? I think it is running rich on the bottom and lean on the top...The elevation is 4,500. Any help would be great!!

[ghott]

Lean on top means increase the main. But...You shouldn't see a night/day difference in lean/rich going from a 178 to a 180 main. There isn't much size difference between the two jets.

Rich on bottom means adjust the Fuel screw in, or go down one on the pilot.

[yfz450les]

(I have a 2005 YFZ450, have a whitebrothers exhaust, aftermarket airfilter. Ran 178 jet-was lean. Ran 180 jet-was rich. Do I need to change pilot and or needle??? I think it is running rich on the bottom and lean on the top...The elevation is 4,500. Any help would be great!!)




try your 178 main jet and a 45 or 48 pilot cause of afteermarket filter. then 2.5 turns on ur fuel screw which is on the bottom of the the carburetor pointing toward the motor tighten it till it bottoms out dont overtighten u will mess it up. hav a mark on a screwdriver then loosen it up 2.5 turns. then 4th or 5th clip from the bottom on the needle. then try it by removing airbox lid.Hope this works!!