A copy though
As long as you change the oil regularly - as the cam runs directly in the head with no bearings and clean, fresh oil is vital to prevent head wear (I change mine every 600 miles, but you can stretch it to 2000 miles max)
....and the gearbox sprocket output shaft, which will strip the splines if you fit a poorly fitting aftermarket front sprocket OR overtighten the chain and fuck it up
Both known costly issues with Honda aircooled singles in XR's and others
Mere semantics....