Janky jetting 07 400ex

I'm having one #=!!of a time gettin my 400 to run correctly without jetting it way lean. It has a k&n filter with a drilled lid and an aftermarket pipe so logic says go up in jetting.... well I had to go down i dont know much about it as I bought it with all the work (besides jetting) done to it. I do know it had a valve job done right before I got it and it's got a stage 2 hotcam and a high comp piston. I've checked timing and it's got really good compression. I have no idea where to go with this thing and domt want to just start dumping money into it