I got an 01 400ex with 85.5mm weisco 10:1 piston, dg full exhaust and uni closed lid filter. I just bought it and the previous owner did not rejet so it has a 148 main and a 38 pilot. Obviously I want to rejet but to what i dont know I was thinking 42 pilot and 155 or 158 main jet does that sound reasonable? Does any one have any suggestions on what they reccomend. Thanks

 

When i was looking to re-jet mine i had to find my altitude and the mods done to the quad. I had a dyno jet kit and it had a chart for the different mods and altitudes and what jets to use.