Description

Ruizheng Racing mio cylinder head for motorcycle. The modification of the valve cylinder head mainly involves valve size, valve angle, valve spring, combustion chamber optimization, etc., the purpose is to improve the intake and exhaust efficiency and increase power output. The following are common modification schemes and parameters:

1. Modification direction and function

✅ Increase valve diameter: increase intake volume and power
✅ Optimize valve angle: reduce intake and exhaust resistance and increase flow rate
✅ Replace and strengthen valve spring: improve high speed stability and prevent floating valve
✅ Polish combustion chamber: reduce air flow resistance and improve combustion efficiency
✅ Match with large flow carburetor/fuel injector: provide sufficient fuel supply
✅ Match with high camshaft: extend intake and exhaust time and increase torque

---

2. Common modification parameters

Modification Project	Original parameters	Modification parameters (suggestion)	Effect
Inlet valve diameter	25mm	27-28mm	Increase air intake
Exhaust valve diameter	22mm	24-25mm	Improve exhaust efficiency
Valve stem diameter	4.5mm	4mm	Reduce weight
Valve spring	Single spring	Double spring / hardened spring	Improved stability
Combustion chamber volume	9-10cc	8-9cc	Increase power output
Valve angle	45°	30°/60° Compound Angle	Increase traffic
High angle camshaft	6.5mm	7.0-7.5mm	Increase valve lift

---

3. Notes on modification

1. Check whether other supporting equipment also needs to be updated synchronously;
2. After checking the accessories, test whether they are safe;

---

4. Applicable models

Mio2 modified valve cylinder head is mainly used for Yamaha small-displacement scooters. Common modified and adapted models include:
✅ Yamaha Mio 125 (M3, MX, Soul GT)
✅ Yamaha Nouvo (Nouvo Z/Nouvo SX)
✅ Yamaha Aerox 125/155 (some models need to adapt the intake manifold)
✅ Yamaha Fino 125

In addition, some Honda and Suzuki models can also be adapted, but additional modified brackets or adjustments to the intake and exhaust interfaces are required.

---

5.Target customer groups

Mio modified cylinder heads are mainly aimed at racing users and high-performance players, including:
✅ Racing modification (such as Matic track races, Drag straight racing)
✅ High-performance street car modification (for civilian use but pursuing power)
✅ Mountain road fun car/long-distance cruise car (enhanced power to cope with slopes)

If it is for pure racing purposes, it is usually equipped with a large-bore piston of more than 63mm, an upgraded transmission system, and ECU track adjustment to make the speed red line higher.