Just bought my second 99 Ultra 150. It has 67 hours on it, is in good shape, runs good, and has good compression across the board. Here's the question. It has had the choke plates removed and a primer added along with aftermarket flame arrestors, I think R & D. Is this asking for trouble? I have come across info in the past that removing the choke plates is a bad idea and worse yet adding freer breathing flame arrestors without at least shimming the slides and going richer on the jets. Do you think I have a mid-range lean condition, overall lean condition? How do you know if you have a mid-range lean condition? Do you literally do some plug chops after some part-throttle passes rather than the typical full throttle plug chops for checking mixture at full throttle? Can anyone direct me to pictures/info on how to properly read the plugs or any other method to know if I have a potentially dangerous condition. The air is already very dense here in WA state. My 1st bone stocker with just a Shredmaster runs 67.8, not even a shimmed pump. Thanks guys, Mike.