I havnt read the other 2 pages so I don't know what you have and have not checked yet but I had a very similar problem before. Sometimes wouldn't start up on the first kick, weird sounding idle, bogged down and sometimes stalled when given throttle, and would die when I would try to ride it in gear. It turned out one of my reed petals ( vf3's ) came loose and dropped down out of place. Finally after hours of doin this and that I took my reed cage out and found the reed petal sittin on the intake bridge, thank god it didn't make it into my cylinder. I would check your reeds ASAP if you havnt already before you cylinder eats a reed petal and spits debree down into your crank !