SP Takegawa Super Head 4V+R 181cc Big Bore Kit – 5-Axis Ported | Honda Grom & Monkey 125

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.