Ralph,
Could you please elaborate on that statement some? The reason I ask is because I'm currently breaking in a small gas motor and I'm looking into building a 50cc gasser. I hate that nasty black spotty Lawnboy Ashless crap all over the bottom of my current airplane that I have to clean up when I fly, but I know it will go away one day. My question is, is it possible/feesable/practical to break in a gas engine on a test bench to avoid all the nasty problems you get while breaking in on a plane? If so, how would you do it. (Run times, throttle, needle settings ect.) I plan on buying my 50cc gasser a piece at a time (as funds become available) and if I can break-in on a bench I'll buy the engine first so I can run it in while i'm collecting the rest of the parts.
Thanks in advance for any advice you can give.

Josh