TBparts
TBparts 149cc Big Bore Kit & Injector for 2022+ Honda Grom/Monkey 125
TBparts 149cc Big Bore Kit & Injector for 2022+ Honda Grom/Monkey 125
1860 Obispo Avenue
1860 Obispo Avenue
C
Signal Hill CA 90755
United States
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Unlock more power and performance with the TBparts 149cc Big Bore Kit & Injector for your 2022+ Honda Grom or Monkey 125. This bolt-on upgrade significantly boosts power and compression, delivering a more exciting ride at an affordable price.
Designed for easy installation, this kit requires no boring of the engine case—just bolt it on, tune (tuning not included), and hit the road! Whether you're looking to enhance performance or need a fresh cylinder, piston, and rings for a rebuild, this kit is a solid choice for riders seeking a reliable power boost.
Key features:
- High quality, Forged, high compression 55mm piston, with rings, pin, & clips
- 11.8:1 compression ratio compared to Stock 10:1. Our 11.8:1 piston is pump 91+ octane gas friendly.
- Aluminum cylinder with steel sleeve (55mm)
- Head gasket kit with exhaust gasket!
- Fits all 2022+ Honda Grom/Monkey 125
- Largest bore you can go without boring the cases
- More power and fun at an affordable price
- Clearance to retain factory piston oil squirter
- Easy bolt-on kit
- +4 HP! More gains if you have a performance Exhaust and Intake
- includes Honda PCX150 injector. Larger than stock injector for use with all Honda Grom and Monkey 125. Tuning required
There are no installation instructions, but if you can replace your piston, you can install this kit. If you don’t have any experience working on your engine, we highly recommend having a professional technician install this kit or, at a minimum, purchasing the shop manual for your bike. We also have a link on our website in the INFO section under Honda where you can find additional info. The parts are installed in the same manner as the OEM parts.
Notes:
- These bore kits are only for the 2022 and newer models (will not work on the 2021 and older models as the engine has been redesigned)
- A performance intake and exhaust is recommended if you want to get the most power possible! (Not necessary)
- Tuning Required – The ECU will require a flash/tune to prevent a lean condition and possible damage to your engine. We recommend aRacer RC Mini X.
This product is legal for closed-course competition use only; for racing vehicles (a competition vehicle not used on public highways). Intended for off-road use or race purposes; may not meet regulations of pollution controlled roads or highways. Not legal for vehicles registered and use in California.
