Super Head 4V+R 145cc Performance Kit for Honda Monkey 125 (JB03/JB05)
The Super Head 4V+R is a kit designed to optimize the performance of the Honda Monkey 125 (JB03/JB05). It features a four-valve cylinder head with a single camshaft, improving airflow and delivering high power at high RPM: 17.5 HP at 10,000 RPM.
Main Features:
- Four-valve cylinder head: Improved intake and exhaust efficiency compared to a standard two-valve head.
- Optimized design: Valve angle, combustion chamber shape, and intake/exhaust ports are adjusted for maximum performance.
- Roller rocker arms: Reduce friction and provide smoother throttle response across the RPM range.
- Valves: Two intake valves (21.5 mm) and two exhaust valves (18.5 mm), both with 4.0 mm stems.
- Progressive valve springs: Reduce valve float at high RPM.
- M8 spark plug: Compact design with optimized combustion.
Aluminum Cylinder with Cast Iron Sleeve:
- Bore: 54 mm
- Stroke: 63.1 mm (stock)
- Compression ratio: 12.0:1
Additional Components:
- Forged aluminum piston: Lightweight yet highly durable.
- Camshaft with automatic decompression: Eases starting and reduces stress on the kickstarter and transmission.
- Compatible with M5 temperature sensor: Allows installation of a Takegawa temperature sensor for cylinder monitoring.
Intake and Injection System:
- Big throttle body (Ø34 mm): Enhances airflow and optimizes fuel delivery.
- High-capacity injector (G-1): Ensures sufficient fuel supply for increased displacement and power.
Electronic Engine Management (FI-CON Type X):
- Programmable fuel injection controller replacing the stock CDI.
- Plug & play compatibility with the Honda ECU (no modifications needed).
- Pre-configured fuel maps (MAPs) tailored for various engine setups.
- Advanced tuning via smartphone or PC (fuel curve adjustments, rev limiter, engine data monitoring).
Important Information:
- Not approved for road use: Competition use only (displacement exceeds 125cc).
- Recommended crankshaft reinforcement: Use a Takegawa crankshaft support to reduce stress on the crankshaft.
This kit maximizes the Honda Monkey 125’s performance, delivering a powerful, high-revving engine setup.
