S&S CYCLE 93 OR 74 KNUCKLEHEAD ENGINE FOR 1936-1999 HARLEY-DAVIDSON
MOTORCYCLES (NATURAL FINISH CRANKCASES & GLOSS BLACK CYLINDERS & HEADS)


S&S Cycle engines are designed to fit Harley's with no modifications.

  • The Flathead Power KN-Series engines are very close in appearance to a stock knucklehead engine, but offer a number of modern features for more power, better engine life, and improved reliability. Aside from the much larger 93 inch displacement, the main improvement in design is the 1958-1965 style flywheel assembly, which uses a splined sprocket shaft and Timken sprocket shaft bearing. Although this necessitates the use of a 1955-1964 style inner tin primary cover and primary chain sprocket, the increased flywheel stability, strength, and power handling capacity are worth a slight departure from stock.

    Flathead Power rocker arm cover tins are another modern improvement. The lower covers are actually made of die-cast aluminum, and instead of being held in place by the valve guide, they are held down by valve spring pressure. A special gasket and o-ring seal on the bottom of the lower tin provides a positive seal, and is much easier to service if needed, since the valve guides do not have to be pressed out in order to remove the lower covers. Instead of the steel brazed-in hard oil return lines used on stock tins, S&S has improved the design of the oil line for better reliability and easier assembly and maintenance.

    The KN93 1936-1947 version engine
    is a standard compression 93" engine.  It is available with authentic generator style crankcases for 1936-1947 Harley-Davidson OHV big twin chassis, primary, and transmissions; it fits stock knuckle frames.

    The KN93 1970-1999 version engine is available with alternator / generator style cases for use with 1970 and later primary covers and late style transmissions. It fits 1970-1999 Harley-Davidson custom chassis, and will not fit stock knuckle frames.

    Features and benefits include:

    • Generator, alternator, and alternator/generator styles available
    • Alternator & alternator/generator models have correct sprocket length sprocket shaft for 1970-up primary & tranny
    • Alternator/generator engines include oil filter mount for generator location
    • Alternator/generator cases have 1948-1999 style front motor mount
    • S&S Super Stock single fire electronic ignition system and polished billet timer
    • Natural crankcases and hi-temperature gloss black cylinders and heads
    • S&S valve train – solid lifters
    • S&S Super E carburetor
    • One year warranty


    The KN74 1936-1999 version engine
    has a stock 74" displacement, and is designed for 1936-1999 Harley-Davidson chassis. It is ideal for bikes with stock drive trains, because it will not cause excess strain on your existing components.

    Features and benefits include:

    • S&S Super Stock single fire electronic ignition system and polished billet timer
    • Natural crankcases and hi-temperature gloss black cylinders and heads
    • Authentic generator style crankcases
    • Standard 74" displacement
    • S&S Super E carburetor
    • 7.5:1 compression
    • 346 camshaft
    • One year warranty