More Trials and Tribulations with the Champ. Put new plugs in last Monday, flew four flights on Monday and 3 flights on Saturday, started to miss again on Saturday. Sunday morning first flight starts missing again. Land and replace the left plug that is black with the plug I removed from the right side on Monday. Sky was bad so I waited about 2 hours for clearing skies. Ran fine for a while, missed a few times, land and notice it is idling ruff, never did this before. Pack up and go home. Wake up this morning and decide I need to remove the left head and clean the exhaust valve. All goes as planned and reinstall the engine. As I install the prop I notice one cylinder has no compression. Take the plug out of the left cylinder and now there is no compression! OK remove the right exhaust pipe and plug and with compressed air determine that the right exhaust is leaking. Take the engine back off and clean the right cylinder exhaust valve. OK I'm going to 50 to 1 ratio oil using Sthil Ultra pre Roto Website. Get to the field about 1330 hours, set the high speed needle, turning 5850, more than ever before, feeling real good. Take off and about 8 minutes in the plane starts to miss. Must be a bad ignition. Land and feel the ignition box, it's hot and mounted in the cabin, everything is cool.