Just picked up the motor and electrics out of one of these babies for a reasonable $300, CRM250 AR is interesting in so far is it had servo activated power valve 2 years before the CR250 did and was set up power valve to close further, to harness 'free radicals' in the exhaust gas to boost combustion at low rpm.
Honda built 3 or 4 versions from mid 80s onward and sold them up until quite recently as domestic model in Japan.
Anyways you end up with torquey trail bike engine at the end, which is heading for a blown up 2008 CR450 roller I have in stock. Kind of makes more sense for me trail riding than CR500 motor.