186cc Big Bore Kit - Grom & Monkey 125 tbparts & CRF50 4" Extended Throttle

& CRF50 4" Extended Throttle Cable and Carb Cap

- Lightweight high compression domed 67mm piston with rings

YX160 Piston for 184cc kit

NEW VERSION as of July 2021 Trimming for the 2019+ CRF110 is no longer a must

The spigot side is 33mm

186cc Big Bore Kit - Grom & Monkey 125 tbparts & CRF50 4" Extended ThrottleTB Parts 186cc Big Bore Performance Kit (64mm) TBW9150 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