Lexmoto: Dart 125 WY125T-100, FMR 125 WY125T-74R. Pulse: Lightspeed 2 125 WY125T-74. Cylinder head studs are threaded fasteners that secure the cylinder head to the engine block in a motorcycle. Made from high-strength materials like steel or alloy, these studs withstand the high pressures and temperatures within the engine.