53-0322 Top dead center piston stop. 12mm

Finding true top dead center is critical for accurate ignition timing and engine diagnostics. This S&S piston stop is designed for engines with 12mm threaded spark plug holes, making it a must-have tool for 1999–2017 Twin Cam models, 1986–2022 XL Sportsters, and 2008–2012 XR1200s. Simply thread the tool into the spark plug hole to physically stop the piston, allowing you to mark the exact TDC position on your flywheel or timing plate. It is a simple, durable tool that takes the guesswork out of engine tuning. Every Harley mechanic’s toolbox should have one of these to ensure that performance upgrades and maintenance are performed with absolute precision.