Description
If you’re running a high-compression Evolution Big Twin with serious displacement, factory valve springs will let you down under sustained boost or aggressive cam profiles. The JIMS Valve Spring Kit replaces that weakness with a precision-engineered interference double-spring design that controls harmonic vibrations and maintains valve integrity even in severe applications. Built in the USA and trusted by builders who demand reliability at the edge of performance.
- Interference double-spring design
- Integrated harmonic damper
- High compression compatible
- Large displacement rated
- Includes locks, retainers
- Spring seats included
- USA manufactured
- Fits 1998-2004 Road Glide
- Evolution Big Twin engines
- MPN: 1350K
- Severe application capable






