Racer, there is some mix up here! The number you quoted in your original post '44641-300-000' is listed as a 'Retainer, gearbox' while the part in your picture is the 'Speedometer Gearbox' itself. Can we be clear as to which part it is you want, then we may be able to help. If it is the gearbox you want, then I can say with certainty that one from a cb250 will be OK as I've used one myself. Get back to us. Cheers.