S&S Cycle - How to identify S&S Flywheel and Crankcases

S&S uses identification stampings for engine assemblies, crankcase sets, and S&S flywheel assemblies. The cases and flywheels are marked by a process called pin stamping.
Every S&S serial number is bookcased by an asterisk to help protect from the number being illegally altered. Some letters are not used because they can be easily confused with other letters or numbers. These letters include, I,O,Q, & V.

The engine serial number is located on, both, left and right side crankcase halves. A typical S&S engine serial number may look similar to this:

*MC00251X*
M = Build year
C = Style of crankcase
00251 = Build sequence
X = S&S Flywheel diameter

Identification code charts can be found in any current S&S catalog.

The S&S flywheel serial number can be found on both flywheel halves. On Evolution and earlier engines, the flywheel code can be viewed from the timing hole towards the top of the left side crankcase. For these engines, disassembly is not necessary to view the number. However, the number will be upside-down when viewed through the timing hole.

A typical S&S flywheel number code may look like this:

M1006-6SF
M1006 = Serial number
6 = Stroke
SF = Year code

The S&S flywheel serial numbers can even help determine when the flywheels were made, whom they were originally sold to, or how the wheels were originally balanced. However, S&S will have to be contacted for this specific information, as it is not listed in any S&S publications.

We hope to have given you some insight for deciphering the S&S system for coding and identifying powertrain components.

This information is important when trying to identify a vehicle, order the correct parts for an engine, or when trying to identify the type or age of parts when restoring a vintage motorcycle.

Thanks S&S for sharing this video with us! To learn more about S&S see their Tech Resources.