By now you know the pan fits. The only hindrance might be clearance if you use a header, this pan is 15-16mm deeper. If it's a 500 you won't need the gearbox trochoid pump feed so either use the 650 oil pickup & block that off or pick up a CB400F pickup, cut off the neck (longer plus uses an o-ring) and weld it to your 500 pickup to extend it. Then just cut off the legs that hold it off the bottom of the pan as the 650 pan has those three legs cast in.