Close ratio gearboxes are one of the many items in the CMS racing product arsenal. These preset gearbox ratios have been tried and tested on track so you don't need to figure out for yourself. Suitable for circuit racing or going crazy on the streets. Gearset is available in 2 ratios, one for highway cruising and another for drag and track. This item will fit the Yamaha Jupiter MX/Crypton X/Spark/Exciter/Sniper 135 4 Speed equipped with an auto clutch.