"What a horse and pony think of a dirtbike..."
augdog,Ah. It's a mess for certain! You can be certain most of the smoke is valve stem seals but fresh rings on a glazed cylinder will smoke a bit until the rings seat. I'm thinking compression and leakdown tests will verify my suspicion. Probably best to run a glaze breaker through cylinder if its within tolerance. Best to replace piston and rings when performing overhaul because compression ring grooves get a tapered wear pattern and new rings will flutter in loose ring grooves. Not a big deal but that's best method. I suspect this culprit is smoking through valve guides and if our amateur rebuilder didn't replace stem seals they are probably hard as a rock and fractured from previous valve removal. If you have good compression, why not pop cam cover off and replace valve stem seals without removing cylinder head and try it for awhile. I wouldn't expect a factory rebuilders result, but you could probably expect your oil smoke and plug fouling to diminish to acceptable level. Easy enough to replace valve stem seals without complete disassembly. Lock flywheel at TDC and put compressed air into spark plug hole to hold valves on seat and remove valve springs and replace stem seals. If you dont have compressed air available put small rope or twine into spark plug hole and jam piston against rope in cylinder to hold valves up while removing springs and remove rope afterwards. Try stem seals for the easy fix. If it still smokes like a freight train it will require a rework and possibly valve guides if they are worn
Thanks for additional info augdog.I suspect most of the trouble with that little Honda is hard/brittle or damaged valve stem seals and replacement is fairly straightforward and inexpensive. The purpose of bringing piston to TDC and keeping valves closed is to prevent valves from dropping down into cylinder when spring retainers are removed for seal replacement. The methods described are to hold valve closed while spring and split keys are reinstalled. Otherwise if valves drop into cylinder, disassembly may be required to reassemble. Good luck my friend. Check back as needed for advice or a never ending stream of curse words to use....