Description

Ruizheng Racing Mio Camshaft Modification Guide

The camshaft modification of Mio series motorcycles is mainly used to improve the intake and exhaust efficiency and optimize the valve opening and closing timing, thereby improving power output, torque and high-speed performance. The modification plan usually includes replacing the High Lift Camshaft, adjusting the valve timing, strengthening the valve spring, etc.

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1. Mio camshaft modification direction and function

✅ Increase valve lift: open the intake and exhaust valves wider to increase intake volume and exhaust efficiency
✅ Optimize valve timing: keep the valve open for a longer time to increase intake and combustion efficiency
✅ Change valve overlap angle: optimize the flow rate of the mixed gas and improve high speed performance
✅ Reduce engine internal resistance: reduce friction and improve engine operation efficiency

Common modification purposes are High RPM Power, Mid-Range Torque, Throttle Response.

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2. Common modification parameters

High-angle camshafts (such as 7.0mm+) are more suitable for high-speed modifications (Drag/track), while small modifications (around 6.8mm) are suitable for street modifications (street car performance improvement).

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3. Blank Camshaft  vs  Reground Camshaft

Type	Blank Camshaft	Reground Camshaft
Processing method	Made of new blank	Grinding and reprocessing based on the original camshaft
Durability	More durable, suitable for high-performance modification	May reduce durability, but more cost-effective
Precision	CNC production, higher precision	Limited by the original structure, the adjustment range is limited
Applicable scenarios	High-intensity competition, new modified engine	Light modification users with limited budget
Performance improvement	Wide range of adjustment, optional high lift	Moderate adjustment, suitable for street modification

Generally speaking, unground camshafts are recommended for competition-level modifications, while ground camshafts can be selected for those with limited budgets or mild modifications.

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4. Suitable models

Mio series camshafts are suitable for Yamaha small-displacement scooters. Common models include:
✅ Yamaha Mio 125 (M3, MX, Soul GT)
✅ Yamaha Mio i 125 (Electronic injection models require ECU tuning)
✅ Yamaha Aerox 125/155 (some require intake and exhaust adjustment)
✅ Yamaha Nouvo (Nouvo Z/Nouvo SX)
✅ Yamaha Fino 125

In addition, some Honda and Suzuki small-displacement models (such as Honda Click and Beat) can also be adapted, but may require customized mounting brackets or timing gear adjustment.

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5. Modification Notes

🚨 Use reinforced valve springs: High-angle camshafts require stronger springs to prevent valve floating
🚨 Synchronously adjust ECU (EFI models): Ensure that fuel and ignition timing are adapted to the new valve timing
🚨 Match intake and exhaust modifications: Use high-flow carburetors and high-flow exhaust pipes to achieve the maximum effect
🚨 Cooling system optimization: High-lift camshafts may cause engine temperatures to rise, and high-performance oil is recommended
🚨 Avoid excessive modifications that affect durability: Moderate adjustments are recommended for daily riding to avoid affecting durability

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6.What can Ruizheng Racing do for you?

1. You can ask us if we have made the same type of products. We will give you the correct answer without involving the customer confidentiality agreement;
2. You can provide samples to Ruizheng Racing and we will give you a 1:1 restoration;
3. If we produce the same product, you can place a batch order.