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High Comp Keith Black Piston For H-D BT 84-99



Keith Black is one of America's most respected Drag-Race engine designers and builders. He was the first to build 4000 plus horsepower V-8 race engines. Keith now has put all his knowledge and experience into the manufacturing of after market Harley-Davidson pistons. The use of the special hypereutectic aluminium alloy, developed and race tested by Keith himself, makes a piston that is light-weight and has more features than an expensive forged piston. These features include reduced wear and decreased fuel and oil consumption. Tighter running tolerances result in an engine that runs quietly and provides more power. The low heat transfer of the hypereutectic aluminium alloy keeps the skirts cool so piston expansion is minimal. Test engines have been run with as little as 0.0005" (1/2 thousands) piston-to-wall clearance. The high ring placement reduces detonation and increases the top ring temperature. Keith Black pistons will make maximum power at 2 to 4 degrees less total timing than conventional pistons. Available in standard and over sizes for Knucklehead, Panhead, Shovelhead and Evolution Big Twin models from 1941 to present and Sportster 1200. Also available in various Big-Bore and High-compression versions as well as a Big Bore kit that will convert your 883 Sportster into a High-Torque 1200 model. Pistons are competitively priced.
Note 1: Complete piston kits contains 2 pistons with Hastings chrome moly rings, piston pins and circlips.
Note 2: A limited number of KB pistons have the ring grooves crossing the piston pin hole. In order to have the piston rings properly supported these pistons come with piston ring support rings. As support rings do not have a sealing function they do not have to be replaced when you instal new piston rings, but sometimes new ones are needed because a ring is lost or broken.
10.5:1 High Compression 

Type Part Number Size
A 239823 3.498" Std
B 239848 +.005"
C 239824 +.010"
D 239825 +.020"
E 239826 +0.30"
F 239850 +0.040"

Additional information

Weight 1.00 kg

A, B, C, D, E, F

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