ORIGINAL: Don M.
Hey Bob how come that muffler is so cruddy. Mine doesn't look like that

You must be using that dirty old castor oil.
Hey, that's way back when it was clean you ought to (or perhaps ought not) see it now. Still runs great. I took the valve cover off last Sunday just to check them and the rockers are just as solid as when new, valve tolerance dead on with the feeler guage. Cams don't seem to have worn at all!
I didn't mention it before because I don't want to start another Great Engine Debate but I run whatever fuel I have, and mix it with other fuel (castor and syn), run it with anywhere from 5% to 15% nitro, though I most often mix 5 and 10 for 7.5%, and it doesn't seem to make a whit of difference. 15% of whatever oil, castor or syn, is fine as long as you don't run it lean, which is near impossible with this engine too lean, it won't run. Starts easy, runs great, idles great, never deadsticks. Damnedest thing you ever saw. I'll take this any day over some supercharged, pumped, ram-air prima donna gizmofest that conks out every other flight.