BMP Primary Clutch Spring Rate

The BMP (Bikeman Performance) Primary Clutch Spring, also called a primary drive clutch spring, lets you tune how your drive clutch engages and shifts. The primary spring sets engagement speed, upshift timing and how well the engine holds its target RPM through the powerband. Several spring rates are offered, so you can match the clutch to your engine setup and riding conditions.

Key Features:

• Tunable engagement and shift: Each spring has its own initial and finish load. This lets you adjust clutch engagement and top-end shift RPM.
• Holds target RPM: A well-matched spring helps the engine stay at its target RPM during long, full-throttle pulls and under heavy load.
• High-tensile alloy construction: Built to handle repeated compression cycles, high under-hood temperatures and torsional stress while keeping its rate profile.
• Works with clutch weights: Pair it with stock or aftermarket adjustable clutch weights to fine-tune your clutch calibration for terrain, elevation, tires or power modifications.
• Color-coded rates: Springs are identified by color so you can tell the rates apart.

Choose the spring rate that suits your setup, whether you want smoother engagement or firmer side pressure at full shift-out. A BMP primary clutch spring is a simple, affordable upgrade for dialing in clutch performance.