Koso 170cc Big Bore Kit for Honda Grom 15-17

Koso North America

$344.95 USD 


Unleash all the power your Grom can handle with this big bore kit.



  • Allows you to use pump fuel with a compression ratio of 11.5 to 1
  • Retains the reliability of a stock motor
  • Includes ceramic-coated cylinder, 61mm forged piston, rings, pin, gasket kit and banjo bolts