S&S Cycle Forged High Compression Piston Kit (.030") - 106-5506
- Forged "high compression" pistons for 74" stock motors with 3.4375" bore and 3.9687" stroke
- 9:1 compression ratio
- All piston kits come with two pistons, rings, wrist pins, and wrist pin keepers
- Compression ratios listed are approximate and are calculated using the correct length cylinders as specified by S&S
- Require the use of connecting rods with a rod length of 7.440" (standard length OEM #24281-74A connecting rods); use of earlier connecting rods with a rod length of 7.470" (OEM #24281-41A) will result in a slight increase in the compression ratio of about 1/2 point, and may also result in clearance problems (check all piston to cylinder head clearances carefully when using the early style rods)
NOTE: Since many older motorcycles have been modified, be sure to confirm that your engine is still stock before ordering replacement pistons. Using 80" pistons with 74"(331/32"" stroke) flywheels will result in very low compression and poor performance. Using 74" pistons with 80"(41/4" stroke) flywheels will result in contact between piston and cylinder head, and potential engine damage.
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