These 3 3⁄16" bore stroker pistons are designed to be used in conjunction with S&S 4 5⁄8" stroke flywheels to convert 1000cc ironhead engines in 1972-'85 Harley-Davidson® Sportster® models to 1200cc (74") displacement.
These pistons can also be used to replace pistons in older S&S stroker engines with 4 1⁄16", 4 9⁄16", 4 1⁄2", and 4 13⁄16" stroke flywheels. All clearances must be checked. See chart below for displacements and compression ratios. These pistons are normally used in stock Harley-Davidson® cylinders. No cylinders are available from S&S for ironhead Sportster models.
| Stroker Pistons for 1972-'85 Harley-Davidson® Sportster® Models |
| Size |
Part Number |
| +.010 |
106-5542 |
| +.020 |
106-5543 |
| +.030 |
106-5544 |
| +.060 |
106-5791 |
| Piston Deck Height |
.806" |
| Recommended Piston Fit: Close: .0030"-.0035" Loose: .0045"-.0055" |
| Stroker Pistons Specifications for 1972–'85 Harley-Davidson® Sportster® Models |
| Displacement |
71" |
72" |
73" |
74" |
77" * |
| Stroke |
4 7⁄16" |
4 1⁄2" |
4 9⁄16" |
4 5⁄8" |
4 13⁄16" |
| Cylinder Length |
5.330" |
5.330" |
5.330" |
5.330" |
5.330" |
| Compression |
7.5:1 |
8:1 |
8.5:1 |
9:1 |
9:1 |
| *If replacing the pistons in a older 77" stroker engine, stroker plates are required, and all clearances must be checked. |
Notes: If replacing the pistons in a older 77" stroker engine, stroker plates are required, and all clearances must be checked.
S&S offers machine shop services through the S&S remanufacturing program. New pistons can be fit to your existing cylinders for a reasonable charge.
