Replacing the original Harley-Davidson exhausts

In this tutorial, we'll perform a simple operation that any garage enthusiast could accomplish with the right tools and following a simple procedure.
This involves replacing the entire exhaust system with a 2-into-2 exhaust with fishtails.

The escape
The test bike this time is going to be a 2004 HD Softail Fat Boy model, which has been fitted with a pair of whitewall tires and high handlebars, and we're going to complete its character with a pair of fishtail exhausts, in the style of the bikes of the Mexican gang from the Sons of Anarchy series... "cholo" style.

We chose Samson 2-into-2 manifolds for the operation, where the rear manifold exits directly from the left side of the engine, creating a cleaner, more classic look.
The silencers are Fishtail, also from Samson, which fit perfectly into the project and will provide a deep and robust sound.

Facility
To begin the work we will dismantle the original exhaust system completely,

including the exhaust support that is attached to the chassis

and we will mount the new supports.

To install the left support, we must remove two plastic caps from the chassis that protect the threaded holes where we will locate the screws for the new support.

With the exhaust removed, we will take the opportunity to replace the exhaust manifold gaskets, to do this we will remove them from the cylinder head.

and we will carefully position the new ones.

Now we're ready to bolt on the new manifolds. The first step is to reuse the clamps that hold the cylinder heads together, which we'll remove from the old manifolds.

We continue assembling the collectors

and we will check that the gear shift lever rod interferes with the rear cylinder manifold.

The people at Samson have taken this into account and that's why the kit includes a new shift rod that passes under the exhaust.

With the manifolds in place, we can now proceed with the assembly of the silencers, all without tightening any screws. In other words, we must leave the system "loose" and begin tightening the screws from back to front, following the instructions and torques in the service manual.

We will continue assembling the manifold heat shields, placing them in position and securing them with the screw clamps.

Final checks
Before testing the exhausts, we must check that the tailpipes are perfectly parallel and correctly positioned. If not, we will loosen the exhausts again and retighten them, holding them so that both sides are in the same position.

It's also very important to clean them thoroughly before starting the engine, as grease or sweat from our hands that have adhered to the surface during assembly can leave permanent stains if they get too hot.
Once these checks are done, we can go out and test our new exhaust. It's important to know that if the bike is fuel-injected, the ECU will need to be remapped, and if it's carbureted, we'll need to install a Dynojet kit or similar.

Frank Burguera

#harleymechanics