Link to a good EFI article in Motorcycle Cruiser Magazine

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http://www.motorcyclecruiser.com/tech/0910_crup_how_electronic_fuel_injection_works/index.html
Copy and paste into your browser. This is a good read if your trying to get a basic overview of EFI.

[BVHOG]

http://www.motorcyclecruiser.com/tech/0910_crup_how_electronic_fuel_injection_works/index.html
Copy and paste into your browser. This is a good read if your trying to get a basic overview of EFI.

Interesting read and especially the paragraph below and his take on open or closed loop.

A closed loop system is one that uses an oxygen sensor to measure the amount of unburned oxygen in the exhaust system and adjust the mixture based on its inputs. For street use oxygen sensors are primarily used to limit emissions at idle and cruise speeds, and to protect the catalytic convertor (if one is being used) from overdosing on fuel. Closed loop systems operate only when there's little demand for power and conditions don't change very quickly, I.E. during idling and cruising. Whenever power is called for, the system must revert to an open loop. Because they cause the engine to run lean, closed loop operation can also cause surging problems at light throttle openings, especially on twin cylinder engines. For street use, closed loop systems are primarily driven by emission control requirements, so I'm positive we'll see a lot more of them in the future.

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Please realize this is not an indepth explanation, only a basic overview. The HD Delphi ECM is currently the most technically advanced ECM in use in the motorcycle industry. That in itself is enough to hopefully make one realize we need to utilize this ECM and its accompanying sensors and not dumb this system down with any sort of "add on" device in my view. Here is another quote from the article, one I think makes the point best.

'H-D uses a Delphi system and ironically, (or not, depending on your point of view,) it's likely the best, most sophisticated system in current use. Like the majority of EFI systems, it's a Speed Density to Alpha-N system, but one that can also operate in closed loop. Atypically it features ion sensing, which means it can use the spark plug as a sensor to tell it what's happening in the combustion chamber. This is a feature that no other EFI system uses-yet, and pretty much guarantees that H-D will be able to get their bikes through emission testing without problems for many more years.'