KPMI Valve Spring Kit for Harley-Davidson

KPMI Racing Spring Kit 20-21750 for Harley-Davidson Evo & Sportster 1984-2003

$502.00

Upgrade your valvetrain with the KPMI Racing Spring Kit, specifically engineered to withstand the demanding conditions of high-performance V-Twin engines. Designed as a complete unified system, this kit provides exceptional stability, reduced valvetrain mass, and superior fatigue life compared to standard OEM components.

Featuring precision engineering for up to 16.5 mm (0.650") valve lift, this racing valve spring kit delivers reliable seat and open pressures to maintain optimal control across high engine RPMs. It offers a dependable, high-strength solution tailored for select Harley-Davidson Evolution, Sportster, and Twin Cam models.

Key Features

Brand	KPMI
MPN	20-21750
Type	Intake / Exhaust
Valve Lift	16.5 mm
Installed Height	47.2 mm
Seat Pressure	83.9 kg
Open Pressure	199.6 kg
Pressure @ Lift	16.5 mm
Product Weight	0.7 kg

Highlights

Designed specifically for high-stress V-Twin engine demands
Engineered for up to 16.5 mm (0.650") valve lift
Optimized for dynamic stability, harmonics, and extended fatigue life
Suitable for intake and exhaust valvetrain positions

Compatibility

Harley-Davidson Evolution (1984–1999)
Harley-Davidson Sportster 883cc (1986–2003)
Harley-Davidson XL 1100cc (1986–1987)
Harley-Davidson Sportster 1200cc (1988–2003)
Harley-Davidson Twin Cam 88" (1999–2004)

Downloads

Frequently asked questions

What is the maximum valve lift supported by this kit?

This racing spring kit supports a maximum valve lift of 16.5 mm (0.650").

What are the seat and open pressures for the springs?

The spring kit provides a seat pressure of 83.9 kg (185 lb) at an installed height of 47.2 mm (1.860") and an open pressure of 199.6 kg (440 lb) at 16.5 mm (0.650") lift.

Can this kit be used on both intake and exhaust valves?

Yes, this spring kit is designed for both intake and exhaust applications.

Which Harley-Davidson engines are compatible with this spring kit?

It is compatible with Harley-Davidson Evolution (1984-1999), Sportster 883cc (1986-2003), XL 1100cc (1986-1987), Sportster 1200cc (1988-2003), and Twin Cam 88" (1999-2004) models.