KB Performance, big bore forged piston kit 3-5/8. +.020"

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"). You must use long-rod flywheels with a 4-1/4" (stock) (88"), 4-1/2" (93'"), 4-5/8" (96") to 4-3/4" (98") stroke.
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.
Peso del pistón 440gr.
Piston pin weight 97g
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".
Connecting rod length 7.440".
Cylinder length 5.530" standard to +.200" larger.
All KB forged pistons are made from 4032 alloy, an 11% silicon alloy formed in a forge 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 still higher than that of cast Hypereutectic. Therefore, KB forged pistons will require a piston-to-cylinder clearance of approximately .001" more. Pistons are sold in sets, complete with wrist pin retaining rings, wrist pins and piston rings.
Please note that all KB forged pistons come equipped with offset wrist pins / piston pins. There is a front and rear section on the piston and it must be installed the correct way round. Refer to 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
1.388 kg


HS Code
84099100


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


Original name
KB Performance, 3-5/8 big bore forged piston kit. +.020"