MY MOTOR IS BORED TO A 426 WITH 11 TO 1 COMPRESION
WEB ALL AROUND CAM, 3 ANGLE PORT JOB, IDS-2 PIPE
K/N, 42 PILOT JET (STOCK IS 38), 6 AIR BOX VENTS
HAVING BOGING PROBLEMS,, RUNNING 100 OCTANE IN IT
HAVE THE DYNO JET KIT IN IT, ANY BODY HAVE THIS
SET UP AND CAN GIVE ME SOME HELP!!!!!!!!!!!!!!

 

Sounds like a jetting problem. Check your plugs for a rich condition and adjust your jet needle position.

 

Where is the problem in the power range and under what conditions.

 

Plug the holes in the air box lid and run it, then take the airbox lid off and run it. I test mine by riding along in fourth and trying to wheelie, can tell if the power is there or not that way, racing and shifting has too many variables. How easy or difficult it is for the motor to pull it up in fourth will tell you. I have a bone stock 400ex but I went up to a 40 pilot and a 150 main, I took the head apart and cleaned it up inside and port matched the intake and exhaust. I also put a xr400 head gasket in to raise the compression. It runs awesome now. I have to run with the airbox cracked open in front or off alltogether. Hope it helps.