Wheres the oil filter on a 1983 Honda XR200R? and how do you clean it?

A 1983 XR200R does not have a replaceable oil filter. It has a cleanable screen. It is located on the left side of the crankcase behind a large nut. I think it is a 17mm. Remove cover and clean screen.

On the right hand side of your bike should be a 2" cover with three bolts holding it on. The bolts should take an 8mm wrench to remove, take the cover off and the oil filter is under that cover. You probably do not have a cleanable filter in there it is most likely a paper element filter but they are cheap to buy. When reinstalling the filter be sure to put it in the exact way it came out. It will fit in both ways but only one way is correct. there should be hole with a rubber grommett on it that should face the cover you took off. If reinstalled backwards oil flow to the top of the engine can't happen and the engine will need rebuilding shortly after.