by John Cagney Nash
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Harley-Davidson no longer produces any carbureted models. While innovation rarely meets universal approval (chain-to-belt drive is a prime example), those who were skeptical about the gradual introduction of electronic fuel injection, or EFI, had at least one solid reason. To Disprove: Faulty carburetors can often be diagnosed and repaired on the side of the road, while narrowband O2 sensors and a sealed “black box” brain cannot.
Standard Harley Carbs
Motorcycling tradition says that the first machine produced by William Harley and Arthur Davidson used a modified tomato can as a carburetor. This was followed by units produced, in sequence, by Schebler, Linkert, Tillotson, Zenith-Bendix, and Keihin. Of course, numerous aftermarket companies have produced countless Harley-Davidson motorcycle carburettors since racing and customization began. The Keihin CV CVK 40 was installed in 1988 Sportsters and 1990’s Big Twins. Given the phasing out of carburettors, the CVK 40 is probably the last carburetor to be installed on a production Harley.
The later years of the Harley-Davidson carburetor
Over the years, Harley-Davidson combined a carburetor with every engine the company produced, from the older knucklehead, panhead, and shovelhead engines to the newer Evolution and Twin Cam engines. However, fuel injection was offered as an option for Harley-Davidson’s popular FL Series Touring motorcycles starting in the 1996 model year, but in 2007 it became standard equipment on all Twin Cam engine models, which now includes all Touring, Dyna and Softail models. Only the Sportster series remained old school and retained the carbureted Evolution engine. For the 2008 model year, that series also lost carburetors in favor of Harley-Davidson’s electronic sequential port fuel injection system. The carburetor era was over.
Importance of accurate information
Many purists, custom builders, and hobbyists who like nostalgia or the emulation of carbureted racing motorcycles adapt carburettors to engines intended to run on EFI. For this to be practical, it is important to know which model and year of the engine worked with the traditional aspiration, so that the retrofit carburetor can function properly. For example, someone intending to carb convert a 2008 FXST would need the service manual and parts manual from the last year Softails were made before EFI became standard; in that case, it would be the 2007 model year.
Carburettors vs. fuel injection
Harley-Davidson, as well as the people who use the company’s products, resist change. With that said, there are pros and cons on each side of the carbohydrate vs. EFI debate. New generations of Harley shoppers are by definition younger, making them more tech-savvy and less resentful of change. While carburetion is a simpler system and there are no electronic packages that require expert mechanical attention, sophisticated and well-calibrated EFI systems deliver more peak power through better fuel management. The phasing out of carburettors was due, at least in part, to pressure on the factory from the Environmental Protection Agency. The air-fuel mixture is much more strictly controlled by fuel injection, which reduces emissions. Based solely on this factor, EFI is here to stay.