Motorcycles must have all of the following, except:

In Oregon, motorcycles are required to have between one and three white headlights; at least one red taillight; one white license plate light; at least one red brake light; amber turn signal lights (if the motorcycle was built after 1972); a red reflector on the rear; at least one rearview mirror; a horn; fenders on all wheels; at least one brake; and an exhaust system in good working order. All lighting must be U.S. Department of Transportation (DOT)-compliant.
DMV Writen Test