Replacement cylinder kit with 8.2:1 compression pistons for 3-5/8" bore x 4-1/2" stroke KN-Series engines. Made from the same engineering grade alloyed grey cast iron as our cylinders for shovelhead engines, cylinders for KN-Series engines exhibit excellent strength, wear characteristics, and dimensional stability. Thicker critical sections and increased fin area provide extra strength and improved cooling. The tough black powdercoat finish looks like stock but resists rust and stone chips much better. These cylinders and pistons may also be used in modified 3-5/8" bore Harley-Davidson® knucklehead engines. 5.625" cylinder length.
Cylinders with pistons include cylinders, piston kit, head bolts, base nuts, and head & base gaskets. All piston kits include rings, wristpins, and clips. Recomended Piston Fit: Close: .0035" to .004" Loose: .0045" to .0055". S&S® cylinder heads for 1940-’47 OHV Big Twins are machined for 7/16-20 head bolts and are not compatible with stock 7/16-16 head bolts. If using S&S heads with 37/16" bore cylinders, stock style
hex head bolts for 1948-’65 Big Twins, part #106-4523 may be used. S&S 35/8" bore cylinders require the use of S&S 1966-'84 style 12 point head bolts part #93-3024, due to clearance issues.
Stock 1930-’78 hex style base nut kit is available in cadmium plate, part #106-4522, for 37/16" bore cylinders only. Stainless raised hex base nuts, part #93-3063-S, are required for 35/8" bore cylinders.