In the context of Harley-Davidson motorcycles, "Stage 4" refers to a performance upgrade package offered by the company. Harley-Davidson has a series of "stages" that represent different levels of performance enhancements for their motorcycles. Each stage typically includes a combination of engine modifications, such as upgraded camshafts, cylinder heads, pistons, exhaust systems, and tuning adjustments.
Stage 4 upgrades are intended to significantly increase the power, torque, and overall performance of the motorcycle. These modifications are typically done to the engine and can result in a noticeable improvement in acceleration, top speed, and overall riding experience. They are popular among riders who seek enhanced performance for racing, high-speed cruising, or simply more power for their Harley-Davidson motorcycles.
It's important to note that installing a Stage 4 kit on a Harley-Davidson motorcycle often requires professional installation and may void the manufacturer's warranty. It is recommended to consult with authorized Harley-Davidson dealers or specialists who can provide guidance and perform the modifications correctly and safely.