Probably needs at the least a honing and rings and top end refresh. I just got done doing this on my 200ES. Rule of thumb on these if it smokes a little then goes away quickly its the valve stem seals that leak down some oil while its sitting and it burns it off the next startup. If it smokes longer its rings.
What your probably seeing is it smokes until she is nice and warmed up to full temp and then everything is sealed up, when its cool the rings are letting oil past. If your going to dig into this expect to pay around $100 minimum. I spent about $100 on a gasket kit, oil seals, timing chain, timing chain tensioner, etc. Its one of those you might as well situations, if your going to tear into the top end you might as well refresh it all and be done with it.
If your lucky you won't need to re-bore, thats fairly low hours in my opinion. You might get by with a honing and new rings. Worst case, another $100 for machining and a new piston and rings.
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1984 Honda ATC200ES "Big Red"
1982 ATC200E "Hondie"
1988 TRX300FW "Project Quad" Still in progress....