Re: What 'break-in' procedure did you use?
I just dumped my 40:1 in and started to ride, no break in no nuthen. Have not had a problem.
A side note: yesterday I pulled the head off and was able to wipe away the carbon from the head and piston top, it wasn't baked on or anything, although in some areas, I had to rub real hard, but it all came off. Now I'm riding with a shiny head and piston.