Koso 170cc Big Bore Kit With 4V Head Honda Grom

This kit from Koso is for riders looking to push their Grom to the absolute limit, far past what Honda's engineers ever imagined. 

To make this possible, Koso has paired their 170cc Big Bore Kit with a 4 valve head conversion.

Installation is no walk in the park; massive changes are required to turn the little Grom into a fire breathing beast. Be sure to check the fitment notes and review the additional requirements document below to make sure you are ready for the challenge. 

Features:

• Greatly improved engine performance
• Increases cylinder displacement to 170cc
• Upgrades engine from 2 to 4 valves
• Stainless steel 24mm intake valves
• Stainless steel 20mm exhaust valves
• Performance cam shaft

Note: Additional parts are required, see the Additional Requirements/Information (pdf) below for additional information.