Since around 2010 Honda has started using PGM-FI or Programed Fuel Injection Technology on all VT750 Shadow models including the C2, Aero, Phantom, and RS. are fuel injected bikes. The key to fuel injection is a more high tech system of sensors and monitoring of the engine and atmospheric conditions to provide proper fuel delivery to the combustion chamber. Instead of a carburetor PGM-FI uses a throttle body.
The core of the fuel delivery system are two primary measurements taken from sensors. The two most important variables gathered from the sensors are engine speed and the angle of the throttle body butterfly (throttle angle). Once taken they are compared to a programmed fuel mapping to ensure the proper amount of fuel is dispensed from high pressure digitally controlled fuel injectors at that moment.
Building on this basic core fuel delivery method the PGM-FI system fine tunes fuel delivery even further by factoring in additional variables taken from a multitude of sensors at any given moment to produce readings for intake-port pressure, engine coolant temperature, intake air temperature, and atmospheric pressure. The entire process of factoring every variable from the multitude of sensors used occurs multiple times per second ensuring precise delivery of fuel for a real time accurate air/fuel mixture ratio to the current operating conditions.
Far different from a carburetor are the Throttle Body and the Fuel Injectors mounted to the intake manifold:
When it comes to performance modifications Fuel Injection is no different in the basic principles from a carburetor in that any time a change is made to the air intake/flow and the exhaust flow something must be done to keep the fuel delivery in balance. Unfortunately the factory fuel mapping only goes so far. This can present challenges when adding a performance intake and aftermarket exhaust to your VT750. Thankfully Fuel Injection does not require the science and art of carburetor rejetting and tuning and all you need is an aftermarket processor to restore proper fuel delivery for increased air input and exhaust output.
Looking for a performance intake for your Spirit/Phantom/Aero or perhaps your VT750RS? The Cobra PowerFlo Intake is incredibly popular. Click the first link on the Left link for the VT750 C2 Spirit / Aero / Phantom Chrome PowerFlo Intake.
Cobra makes an Fi2000R Digital Fuel Processor for the Fuel Injected VT750 C2 Spirt, C2B Phantom, Aero, and RS models. They also made a Power Pro model for the C2 Spirit / Phantom / Aero. Note: Cobra is working on creating a Power Pro model for the RS.
Dynojet also makes a programmable fuel controller called the Power Commander 5. This one unit appears to be compatible with all of the PGM-FI VT750 models including the C2 Spirit, Phantom, Aero, and RS.