As low as $127.92/mo with or . (Pay in 4 interest-free payments)
KOSO Big Bore Kit Upgrade power and reliability with the KOSO Big Bore Kit — a complete high-performance overhaul designed to increase displacement while maintaining everyday drivability. Complete kit: ceramic-coated cylinder, 61mm forged piston, piston rings, wrist pin and clips, full gasket set, and banjo bolts High-strength internals: forged 61mm piston for increased durability and consistent performance under load Advanced cylinder finish: ceramic coating reduces wear and improves heat management for longer service life Optimized compression: 11.5:1 compression ratio allows safe use of premium pump gasoline while preserving stock motor reliability Easy install: gasket kit and hardware included for a straightforward rebuild This kit is ideal for riders seeking a noticeable torque and horsepower increase without sacrificing daily reliability. Perfect for sport scooters and small-displacement motorcycles where smooth power delivery and longevity matter.
Includes a ceramic coated cylinder, 61mm forged piston, rings, pin, pin clips, gasket kit, and banjo bolts
Compression ratio of 11.5 to 1 allows the use of premium pump gas to keep the reliability of the stock motor
or 
. (Pay in 4 interest-free payments)