Ban Jing upgraded Stage 1 starter bandix / starter clutch is designed with 5 bearings to lock and turn over performance Yamaha Zuma 125 engines. Ideal for those with big bore upgrades where the compression ratio has been increased! With the weight of 12.6oz, it's lighter than stock! Reducing weight off the crankshaft assembly will in turn gives you quicker rev and engine response! Don't replace your broken Yamaha Zuma 125 starter bandix, upgrade it!