DHM 149cc Big Bore Kit – Generation 2 for 2022+ Honda Grom & Monkey 125
Transform your 2022+ Honda Grom or Monkey 125 with DHMotoring’s second-generation 149cc big bore kit. Engineered for maximum performance and simplified installation, this Gen 2 kit delivers 30% midrange gains and double the stock horsepower at 8500 RPM.
Performance Gains:
- 30% horsepower and torque increase in midrange over intake/exhaust/cam setups
- Double the horsepower of stock at 8500 RPM
- Significant power gains across entire rev range
Generation 2 Improvements:
- Wider skirt bridges for improved squirter clearance
- Enhanced lubrication with additional oil control ring hole
- Two additional piston skirt lubrication holes
- Optimized 12:1 compression ratio for pump gas to reduce hot detonation
- Streamlined manufacturing for better value
Complete Kit Includes:
- 55mm forged piston with ring kit
- 55mm sleeved cylinder
- Base and head gasket set
Required Components (sold separately):
- DHM ECU flash or aRacer MiniX + AF3 combo
- Honda injector 16450-KZY-701 (PCX 150 injector)
- Oil cooler (Kitaco x DHM recommended)
- NGK CR9E spark plug
- Crankcase vent (AvailMS Cam Cover Vent recommended)
Installation Notes:
- Ring gaps must be set during installation – see setup sheet
- Use both base gaskets for pump fuel (91-93 octane), OEM gasket only for race fuel
- Oil cooler required – monitor oil temps closely
- 91 octane minimum, 93 octane preferred
Fitment: 2022+ Honda Grom, Monkey 125, Dax 125, Super Cub, Trail 125 (JC92 platform)
Unlock serious performance with DHMotoring’s proven big bore technology.
