Chubu Motors (Nagoya), 1950 ?
Chubu Motors is listed in several places, including the Japanese language wikipedia site. Supposedly they made a machine called the Silver Bell (シルバーベル号) however I have not found any other information as to whether it was a clip on, a scooter or an actual motorcycle.
Note that another company ( Okochi Ironworks) also made a machine called Silver Bell. They may be one and the same as Chubu Motors is listed in a 1950 listing, whereas the Okochi production was from 1953 through till (roughly) 1955.