I just rebuilt my entire Banshee motor, new Wiseco Hot Rod crank, all new bearings and seals, Wiseco top end .040 over, a coolhead, shift star mod, flywheel lightened, and new PTR mid pipes. All of that stuff is new for the rebuild, and I am also running the Trinity 2 into 1 carb, 35mm. I mixed up some new gas with a 16:1 mixture with Klotz benol for the breakin period. I fired up the bike and ran it through a couple of heat cycles and everything seemed to be fine. Last Saturday I fired it up again to start doing some low gear break-in riding, and that is where the problem started. The left cylinder started mis-firing. The right was firing just fine, but the left didn't seem to be firing all the time. I am wondering if this could be an iginition problem, or if I've scorched a ring or something. I did a leak down test after putting the engine back together, and I only lost .3 lbs over 6 minutes, so I'm cofident that I don't have an air leak. Also, I don't think it's intake because of the single carb and one cylinder is firing fine and the other isn't. I know that someone on this site will be able to help out, so please give me any suggestions on what to check. Sorry this post is so long.