main jet?

[Atomikrage45]

I have been having issues when full throttle from idle... quad just dies...
i believe its my main jet... can anyone else help me... and what size main jet to set up

stock 400 ex
DG exaust
K&n intake
drilled airbox

general riding temps are 70-90º
south jersey, not sure on elevation

[RaginRedneck]

I've got a similar set up, DG X2 Slip on, K&N, stock filter cover and a CDI box. I'm at a 155 main 2 1/8 turns out.

With the drilled air box I would have to guess starting at a 158, but I would buy a 155, 158, 160, start with the 158 and adjust from there.

Good luck.

[drew416ex]

what size main is in it. It sounds either rich, or the boot came off on the air box side.