I put a 4-1 Voodoo on about a week ago. Was told that would richen things up so I removed the Y-cover. Stumbled a bit around 5-6K. Read in other places shimming up the Y about 3/16" and adding .025" shims on the needles so tried that. Bike runs fine but I'm still curious what jetting needs to be done if I remove the Y entirely.