I had a DJ 150 in it and wanted it a bit leaner. Its the smallest the kit comes with. I found an old Mikuni main in my bits and drilled it to 145 with a drill. It feels leaner than the DJ 150, and gave me what I was after.
I could have soldered up a DJ jet and drilled it out, but I already had the Mikuni jet, so I thought I'd experiment and see what happened. All seat of the pants stuff though, so who knows.
I also neglected to add that the pipe comprises a FMF Powerbomb header and Megacycle muffler and tailpipe.