S&S Flathead Power Series KN style Knucklehead engines - 3 5/8" / 4 1/2"

The S&S KN Series engines are very similar in appearance to the original Knucklehead engines, but feature a range of improvements that deliver more power, longer life, and increased reliability. Beyond the increased capacity of 93CI (1523CC), the major improvement lies in the 1958-1965 style flywheel, which uses a splined pinion shaft and a Timken bearing. Although this requires the use of a 1954-1965 style primary cover and primary chain sprocket, the flywheel’s enhanced stability, strength, and ability to handle increased power more than justify the difference from the original. Flathead Power rocker box covers are another improvement. The lower covers are made of cast aluminium, and instead of being secured by the valve guides, they are now held in place by valve spring pressure. A special gasket at the bottom of the lower cover provides a positive seal and is much easier to inspect, as the valve guides do not need to be removed to release the lower covers. Rather than the welded oil passages of the original covers, S&S has significantly improved the oil passage design for greater reliability and easier assembly. KN93 series engines come fully assembled with an S&S Super E carburettor and an S&S Super Stock ignition system, and carry a one-year warranty. Generator-style engines are suitable for original Knucklehead chassis or original-style chassis with an internal primary and 1954-1965 style primary chain sprocket. Alternator/Generator-style engines are not suitable for original Knucklehead chassis, as these engines feature a 1948-1999 style front engine mount and must be used with a post-1970 style internal primary.


Specifications


Pack
1


HS Code
8714109090


Origin
US


Motorcycle family
Big Twin | Dyna | FX | FXR | Softail | Touring