Hey guys, I'm new to the racing four stroke world. (Had some XR's in the day) I picked up a 2003 yz450f the other day for the right price. I added some seafoam to the gas, and now it won't start. I took it all apart, checked the valves, (both a little tight, adjusted intake and exhaust to spec, checked for properly seated shims) timed it according to the "I" mark on the flywheel and sticking an Allen wrench in the spark plug hole. Has good spark, good compression, almost perfect timing, cleaned out the carb. Didn't try replacing the gas. Before it would start first kick every time. After I added seafoam, it smoked a little bit when I started it up, but then soon went away about after 2 seconds of running time. So my question is, what am I doing wrong?