⚠️ For Competition Use Only. Not intended for street use. Installation requires SP Takegawa FI Controller TYPE-X, Big Throttle Body Kit, and Large Capacity Injector (G-2) — none of which are included.
SP Takegawa Super Head 4V+R 181cc Big Bore Kit – The Pinnacle of Grom & Monkey 125 Performance
The SP Takegawa Super Head 4V+R 181cc Big Bore Kit represents the highest level of engineered performance available for the Honda Grom and Monkey 125. Featuring a 5-axis CNC-ported cylinder head, four-valve combustion chamber, forged roller rocker arms, and an all-aluminum ceramic cylinder, this kit is built for riders who demand maximum output and precision engineering in every component.
Super Head 4V+R – Key Engineering Features
- 4-valve combustion chamber (2 IN / 2 EX) — increases valve curtain area for superior intake and exhaust efficiency vs. 2-valve heads
- 5-axis CNC-ported intake ports — 3D-programmed for optimum flow at high RPM; beautifully smoothed for maximum intake efficiency
- 5-axis CNC-machined intake manifold — matched to the ported head for seamless airflow transition
- NC-machined combustion chamber — high-precision finish balancing plug placement, valve pinch angle, and chamber shape for peak output
- Unequal-pitch valve springs — prevents valve float and surging at high RPM
- Forged aluminum roller rocker arms — reduces friction against camshafts for smooth, efficient valve actuation
- Auto-decompression camshafts (10/10D, standard) — enables smooth, starter-friendly engine starts
- Optional 15/15D camshafts available — for improved mid-to-high RPM output (sold separately)
Cylinder & Piston
- All-aluminum ceramic cylinder — black painted finish; excellent durability, airtightness, and heat dissipation
- Oil cooler outlet port — compatible with SP Takegawa Oil Cooler Kit (recommended for sustained high-performance use)
- M5 sensor mount on oil plug bolt — compatible with SP Takegawa compact LED thermometer set for cylinder temp monitoring
- High-compression forged piston (12.5:1) — NC-machined piston top for precision fit and high-performance durability
Valve Specifications
- Intake valve diameter: 25mm x 2
- Exhaust valve diameter: 21.5mm x 2
- Valve stem diameter: 4.5mm (IN & EX)
- Compression ratio: 12.5:1
- Displacement: 181cc
Fitment
- Honda Grom (MSX125) — OG / SF generation (4-speed)
- Honda Monkey 125 — 1st Gen (4-speed)
Required Additional Parts (Not Included)
- SP Takegawa FI Controller TYPE-X
- SP Takegawa Big Throttle Body Kit
- SP Takegawa Large Capacity Injector (G-2)
- SP Takegawa Special Clutch Kit (strongly recommended to prevent clutch slip)
Part Number: 01-05-0130
Professional installation strongly recommended. Instruction manual, if included, will be in Japanese.
