Here is a comprehensive product description for the 4S1M Throttle Body 34mm designed for the Yamaha Mio i 125 (M3).
4S1M Performance Throttle Body (34mm) for Yamaha Mio M3 / Mio i 125
Unlock the true power of your fuel-injected engine with the 4S1M (4-Stroke 1 Motor) 34mm Performance Throttle Body. Engineered specifically for riders looking to maximize their machine’s efficiency, this premium upgrade eliminates standard intake restrictions, delivering a noticeable boost in overall engine responsiveness and top-end power.
Whether you are running an aggressively modified daily commuter or a full-bore 160cc bore-up race project, 4S1M provides the precision airflow your engine demands.
Key Features
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Oversized 34mm Bore: Significantly expands intake diameter compared to stock, facilitating a massive, unrestricted volume of fresh air into the combustion chamber.
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Optimized Air-Fuel Mixture: Designed for larger air intake, allowing for a much more efficient combustion process and higher power output when paired with the right fueling adjustments.
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Immediate Throttle Response: Precision butterfly valve engineering eliminates throttle lag, giving you crisp, snappy acceleration the moment you twist the grip.
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Premium Build Quality: Constructed from high-grade, durable alloy materials meant to withstand extreme engine temperatures, vibration, and high-rpm stress.
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Seamless Compatibility: Built to align perfectly with the factory layout and electronic sensors of standard Yamaha 125cc fuel-injected platforms.
Product Specifications
| Attribute | Specification |
| Brand | 4S1M (4-Stroke 1 Motor) |
| Component | Performance Throttle Body |
| Bore Size | 34mm |
| Engine Type | Fuel Injected (FI) |
| Material | High-Grade CNC/Alloy Compound |
Fitment / Compatibility
This 34mm throttle body is a direct performance fit for Yamaha’s 125cc Blue Core engine lineup, including:
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Yamaha Mio i 125 (Mio M3)
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Yamaha Mio Soul i 125
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Yamaha Mio Gear 125
💡 Pro-Tip for Builders: Upgrading to a 34mm throttle body dramatically changes your engine’s air intake volume. To ensure optimal performance and prevent leaning out, it is highly recommended to pair this upgrade with an adjustable ECU, upgraded fuel injector, or professional tuning.
This Mio i Throttle Body Upgrade Video showcases the performance differences and real-world installation insights when upgrading to a 4S1M throttle body on a Yamaha Mio project.





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