Koso North America 150cc Big Bore Kit for Honda Grom & Monkey 2022+ | MB640000

Push your Honda Grom or Monkey past stock limits with the Koso North America 150cc Big Bore Kit (MB640000). Engineered for 2022+ models, this kit bumps displacement to 150cc with a ceramic-coated aluminum cylinder and a 54mm forged piston — delivering more torque and top-end power while maintaining pump-gas reliability thanks to an 11.38:1 compression ratio.

Everything you need is in the box: forged piston, piston ring, wrist pin, and a complete gasket kit. No exotic fuel required, no sacrificing street reliability.

Specifications

• Displacement: 150cc
• Cylinder material: Aluminum with ceramic coating
• Piston size: 54mm (forged)
• Compression ratio: 11.38:1
• Kit includes: cylinder, piston, ring, pin, gasket kit
• Fitment: Honda Grom® & Monkey® 2022+

⚠️ For racing/off-road use only. Not intended for street use. Koso is not responsible for any damages caused to parts, vehicle, or persons. Engine parts are not under warranty, nor is collateral damage or cost of labor in cases of malfunction.