Sunday, 6 February 2022

Yamaha YZF R125 performance tuning modifications

A post collecting information on popular modifications to the Yamaha YZF R125 may do a post on each time and money allowing. Im not a big fan of wasting lots of money for little return but your opinion may differ.

⚠️ Safety Warning: Performance modifications can significantly alter the handling and power delivery of your motorcycle. Some upgrades, such as big bore kits or exhaust changes, may require recalibrating the fueling system (via a Power Commander or similar) to prevent the engine from running lean, which can cause permanent damage. Additionally, check local laws as some modifications may void insurance or exceed legal limits for certain license categories.

Yamaha YZF-R125 Performance Tuning & Modifications

This guide outlines popular upgrades for the YZF-R125, ranging from simple airflow improvements to significant engine and suspension overhauls.


Engine & Fueling Upgrades

  • Big Bore Kit & Injectors: Increasing the engine displacement is the most direct way to gain power. This usually requires a larger fuel injector to match the increased air intake.

  • Power Commander / O2 Sensor: Allows for custom fuel mapping. Finer control over fuel injection can optimize power delivery across the rev range.

  • EGR Delete: Removing the Exhaust Gas Recirculation (EGR) system prevents hot exhaust gases from re-entering the intake, leading to a cleaner and more efficient combustion.

  • Air Valve Mod: Adjusting the reed valve (which burns off unspent gases) can impact exhaust flow.

Airflow & Exhaust

  • Air Box & Sports Filter: Modifying the air box or installing a high-flow "sports" filter reduces intake restriction, allowing the engine to breathe more freely.

  • Sports Exhaust: Enhances exhaust gas flow and provides a more aggressive sound. Using a baffle is often recommended to maintain necessary backpressure.

Drivetrain & Handling

  • Sprocket Gearing: Changing the size of the front or rear sprockets allows you to prioritize either faster acceleration (bottom-end) or a higher top speed.

  • Adjustable Rear Shock: Replacing the stock unit with an aftermarket adjustable shock allows you to tune the suspension to your weight and riding style, improving cornering and stability.


Parts & Upgrades


Yamaha YZF R125 performance tuning modifications



Yamaha YZF R125 EGR delete 

EGR system is fitted to reduce emmision by circling exhaust gases into you inlet system to reduce temperature of the combustion chamber. Obviously this is going to have an effect of the combustion and the power. 


Yamaha YZF R125 air valve mod

The air valve is a reed valve when the exhaust go negative it sucks in air from the air valve and this helps burn off  any unburned gases.


Yamaha YZF R125 Air box mod

Theory here is more air in more, more air available for combustion , more exhaust out and more power, 


Yamaha YZF R125 Air filter ( sports )

Same as sbove less restriction for air equal  more air for engine and in theory more power.


Yamaha YZF R125 Sports exhaust

As above the moving air through the engine more efficiently adding more power , and noise. although an exhaust baffle has been shown to improve things on sports exhausts.


Yamaha YZF R125 Sprockets

Increase top or bottom end by adjusting sizing of sprockets. 



Yamaha YZF R125 Power commander ~ O2 sensor 

Finer control of fuel injection and custom fuel maps more fuel at the correct time equals more power.


Yamaha YZF R125 Big bore kit and Injector upgrade 

Increase bore size more power, increase injector size more fuel, therer are different size injectors for differing bore size increases. 


Yamaha  YZF R125 after market shock ( adjustable ) 

Increase handling and steering buy adjusting you suspension to suit your riding style 




No comments:

Post a Comment