Grom 186cc Big Bore Kit

TB 186cc Big Bore Kit – Grom & Monkey

186cc Big Bore Performance Kit (64mm) – Grom:

– Ceramic coated all aluminum cylinder (no steel sleeve)
– Lightweight 64mm piston with rings, pin, & clips
– Head gasket kit

IMPORTANT UPDATE: These bore kits are only for the 2021 and older models (will not work on the new 2022 models as the engine has been redesigned)

This is the biggest Grom & Monkey 125 bore kit on the market! The all aluminum ceramic coated cylinder is lighter than a steel sleeved aluminum cylinder, reduces friction (increasing power), improves sealing, and provides better heat transfer (runs and cools down quicker). This new big bore kit will provide the extra power to make your new bike a lot more fun to ride!  High quality parts and requires no machining to the cases.

There are no installation instructions, but if you can replace your piston, you can install this kit as the parts are installed in the same manner as the OEM parts.  However, its recommended that a professional install this kit.  It also must be used with an aftermarket fuel controller to prevent a lean condition and damage to your engine.