no idea what was done. bike was just sitting for anywhere from a decade to 3 years. LOL
got the system apart. the killer is the metal "nipples" that come off the engine case. they are done. ........ i will pressure wash the engine (heads etc) and flush out all the junk. then replace parts. and run and flush.
The left side case water pump nipples were completely rusted to hell. SOOOO it was easier to get a new (to me) case off eBay. i also ordered all the parts i need to get the cooling system back up. radiator looks ok, the top right vent/fill port from the bottle is a little corroded, but shall work.
going to get some Castrol 20w50 4T bike oil, non-syntetic.
Probably using some cheap[ish] oil to use as a flush. Likely any oil would do to see if the rest of the engine is sound. Were it mine I'd take the heads off check the sealing surfaces, and replace the gaskets.