OS Giken OS Giken RB30 Timing Belt

OS Giken was founded in 1973 in Okayama by Masaharu Okazaki as the Okazaki Speed Technology Research Institute, a tuning shop for cars and motorcycles. It became OS Giken Co., Ltd. in 1988. Okazaki built his own high-revving twin-cam engines, the TC16 and TC24-B1, and began making stronger drivetrain parts because stock ones could not take the power.

A Violet with a TC16-MA II won the 1980 All Japan All-Star Dirt Trial, and a 280Z with a TC24-B1 took third in its class at the 1982 SCCA Pro Rally in Nevada. OS Giken still makes clutches, limited-slip differentials and gearboxes, including the OS-FR7 7-speed sequential, from its base in Okayama.