KB Performance, forged big bore piston kit 3-5/8. +0.005"

3-5/8" big bore forged piston set. Compatible with 3-5/8" big bore cylinders with a length of 5.330" (stock) to 5.530" (+.200"). Must use long stroke crankshaft flywheels of 4-1/4" (stock) (88"), 4-1/2" (93'"), 4-5/8" (96") to 4-3/4" (98").
Compression ratio 8.50:1 with 117cc cylinder head, 4.250" stroke and standard cylinder length.
9.38:1 compression ratio with 117cc heads, 4.750" stroke and standard cylinder length.
Piston weight: 440 g.
Piston pin weight: 97 g.
Piston pin diameter: .791" / offset.
Cylinder head type: Dome with -42.3cc.
Compression height: 1.285".
Diameter: 3.625".
Stroke: 1.250" to 4.750".
Conrod length: 7.440".
Cylinder length: 5.530" standard up to +.200" longer.
All KB forged pistons are made from 4032 alloy, an 11% silicon alloy formed in a forging press. Forging the aluminium provides superior strength and structural integrity at a molecular level, after which it is fully machined. The combination of this alloy and the forging process allows the piston to flex under detonation or pre-ignition, offering the best resistance to cracking. Although 4032 has a low expansion rate, it is superior to cast Hypereutectic. Therefore, KB forged pistons will require a piston-to-cylinder wall clearance approximately .001" greater. Pistons are sold in sets, complete with wrist pin retainers, wrist pins and piston rings.
Note: All KB forged pistons come equipped with offset gudgeon pins / piston pins. There is a front and rear section on the piston and it must be installed the correct way round. Consult the installation instructions provided with each piston set before installation.
Note: The stock 5.330" cylinders can be used with the stock 4-1/4" stroke. Longer strokes require longer cylinders of the correct length or long-stroke plates to achieve the desired compression ratio.


Specifications


Brand
KB Performance Piston


Application
48-84 Pan, Shovel. With 3-5/8 big bore cylinders (NU)


Sales unit
Set


Material
Aluminium


Packaging weight
1.387 kg


HS Code
84099100


Motorcycle family
BIG TWIN, FX, FXR, SOFTAIL, TOURING


Original name
KB Performance, 3-5/8 big bore forged piston kit. +.005"