iIhave a 1985 honda 350x and it still has the original jets #138 and #42 but i think that is for low altitude and i ride at anywhere from 4000ft to 10000ft and it is running realy rich so if any one knows what size to run that would be greatly apreciated.

thanks

 

I think one down on the main jet, and a 1/4 turn in on the mixture screw is what the book says. If rejetting isnt convienent, drill some holes in the air box lid, and at low altitude, keep them covered with duct tape. As you go up in altitude and notice the rich running, start pulling the tape off, to uncover the holes. When you go back down..cover them back up. 4 to 6, one inch diameter holes should do it.