Before you start, you'll need a few tools and materials.

You'll need a socket wrench set, a torque wrench, a flathead screwdriver, and a hammer.

You'll also need a new exhaust system that is designed to fit your Honda Shadow 125.

It's important to choose an exhaust system that is designed specifically for your motorcycle, as aftermarket systems may not fit correctly or may cause damage to your motorcycle.

Step 1: Prepare Your Motorcycle.

The first step in installing a new exhaust system is to prepare your motorcycle.

Start by parking your motorcycle on a flat surface and turning off the engine.

You'll need to remove the old exhaust system before you can install the new one, so make sure you have enough space to work and that your motorcycle is stable and secure.

Step 2: Remove the Old Exhaust System.

The next step is to remove the old exhaust system from your Honda Shadow 125.

This may require a bit of force, as the old system may be rusted or stuck in place.

Start by removing the muffler from the exhaust pipe.

You can do this by loosening the clamp that connects the muffler to the pipe, then sliding the muffler off the pipe.

Next, you'll need to remove the exhaust pipe from the engine.

This may require removing some bolts or screws that hold the pipe in place.

Use a socket wrench set to loosen and remove the bolts, then slide the pipe off the engine.

Be careful not to damage any of the components as you remove the old exhaust system.

Step 3: Install the New Exhaust System.

With the old exhaust system removed, it's time to install the new one.

Start by attaching the exhaust pipe to the engine.

Make sure the pipe is properly aligned and use a torque wrench to tighten the bolts to the manufacturer's specifications.

Next, attach the muffler to the exhaust pipe.

Again, make sure the muffler is properly aligned and use a torque wrench to tighten the clamp to the manufacturer's specifications.

Step 4: Test the New Exhaust System.

Once you've installed the new exhaust system, it's important to test it to make sure it's working properly.

Start the engine and listen for any unusual sounds or vibrations.

If you notice anything out of the ordinary, turn off the engine and check to make sure the components are properly aligned and tightened.

Step 5: Adjust the Carburetor.

After installing a new exhaust system, you may need to adjust the carburetor to ensure your motorcycle is running properly.

This is because a new exhaust system can change the air flow and fuel ratio in the engine.

Refer to your owner's manual or consult a professional mechanic to determine the correct settings for your specific motorcycle.

Step 6: Clean and Maintain the New Exhaust System.

To keep your new exhaust system in top condition, it's important to clean and maintain it regularly.

Use a soft cloth and mild soap to clean the exterior of the system, and avoid using abrasive or harsh chemicals that may damage the finish.

You may also want to invest in a heat shield or wrap to protect the new exhaust system from heat damage.

In conclusion, installing a new exhaust system on your Honda Shadow 125 can be a great way to upgrade your motorcycle's performance, sound, and aesthetics.

By following these steps and taking proper care of your new exhaust system, you can enjoy the benefits of a custom exhaust system for years to come.