Came across this recently, not sure if it's commonly known, but a customer of mine validated the engine bolts right up into his 85 200x frame.
https://www.ebay.com/itm/25265202404...m=252652024047
Based on some research, it's a CRF230 clone engine made in china. Engine model is 169FMM based on the listing, seems like 167FMM is more common though. I don't know which way the kick starter kicks though, since it's a motorcycle engine, guessing backwards from what a 3 wheeler should have.
While googling around, I saw a mention of the top end of this engine being used on an atc200x bottom end, so I guess some parts might be interchangeable.
Might be a long shot, but I wonder if the top end from the liquid cooled version of this engine could be swapped on the 200x. Seems like a liquid cooled 200x would be a pretty neat upgrade + the cylinder slightly larger ~230cc.