Fuel & Air Systems

Fuel & Air Systems



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Sale price€483.33

To find spare parts, Holy Death Shop offers you a wide range of Harley Davidson engine parts.

Indeed, you will find original engine parts for the different models:

  • 18+ Softail
  • DYNA
  • FXR
  • Sportster
  • Touring
  • Universal

It appears in fact, the engine of a Harley Davidson incorporates several filters, including the oil filter, fuel filter, fuel filter...

Also, the Harley-Tax or Stage1 consists of making certain modifications to the less restrictive air filter, the exhaust without catalysts and released as well as the cartography of the injection map.

Indeed, savvy motorcyclists will turn to a mechanic for the balancing of the supercharging.

The air filter for all Harley Davidson models

At first glance, the motorcycle's air filter designates a point of entry for air into the engine. Moreover, it acts as a bulwark between the impurities in the air and the carburetor or the injection rail.

This is because a combustion engine mixes a certain amount of air with another gasoline before causing an explosion. Thus, the filter lets the engine breathe so that it does not explode.

Besides, the air filter is tucked under the tank in general. So you can find it above or behind the engine and the carburetor.

On the other hand, you can access the air filter by lifting the tank. Then you need to unscrew the cover covering it and sealing the airbox. Likewise, you must inspect, and maintain the air filter according to its type (paper air filter, foam air filter, or performance air filter).

Stage 1 to customize the fuel-air system

First, stage 1 allows you to modify your Harley-Davidson's exhaust system, air filter, and fuel metering system. Thus, this part allows the engine to:

  • Increase the available power
  • Breathe more
  • Operate efficiently

It appears in fact, the free flow of the air filter and the appropriate tuning of the exhaust line optimize the high performance of your two wheels. Likewise, by increasing the amount of air and fuel circulating in the engine, more power is produced. Also, step 1 can incorporate free-flowing air filters and breather air filters. Thus, the exhaust system will produce a smooth sound.

Besides, stage 1 generally refers to the recalibration of the intake systems as well as the exhaust air systems. As a result, the air-flow improves. However, a Phase 1 upgrade does not require internal engine modification.

Internal combustion engine: carburation or injection?

Generally, motorcycles use internal combustion engines. Moreover, this type of engine is based on carburetion or the phenomenon of internal combustion by fuel explosion. Indeed, the latter occurs in one or more cylinders. Thus, combustion requires fuel (gasoline: allowing an explosive mixture) and oxygen (the external element that triggers the explosion).

Besides, supplying an engine block with a fuel-air mixture enables a sufficiently explosive result to be obtained. Thus, the energy necessary for the performance of the engine is produced through carburetion or injection.

Carburetion and carburetor

Carburetion refers to the operation of mixing air with fuel. Thus, the device for this mixing is called a carburetor. Moreover, the amount of the mixture of air and gasoline is usually called the AFR.

Also, the carburetor consists of a large diameter duct (the Venturi), extending the intake duct of the engine. Indeed, the latter allows the air to be engulfed under the effect of the suction created by the intake time. The change in the shape of the duct (conical shape to cylindrical shape) produces laminar flow. Thus, the venturi is connected to the nozzle which plunges into the tank (small reserve of gasoline).

On the other hand, the atmospheric pressure creating a suction force in the cylinder generates a very violent air current. This phenomenon then allows the nozzle to suck gasoline from the tank. The gasoline then propels itself up in very fine droplets to mix with the air.

Finally, the assembly is compressed by the piston by the compression time and ignites by the spark from the spark plug.

What is the injection?

First, injection also allows atmospheric pressure to be used to get air into the cylinder. However, the injector makes it possible to control (mechanically or electronically) the quality of fuel. The principle behind Harley-Davidson is to inject the desired amount of gasoline directly into the intake duct.

To do this, the nozzle becomes the injector. It appears in fact, gasoline arrives at the injector through an injection pump. Electronic, the latter follows a computer programming, configured according to the engine speed. Thus, this pump is characterized by its adaptability to different parameters:

  • Air temperature
  • Engine temperature
  • Atmospheric pressure
  • Besides, injection improves engine power while reducing fuel consumption.


France Orders - 7.90€

International Orders - 19.90€

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