for Evolution and Twin Cam

Deep recesses completely enclose the upper cover screws for a continuous, sharp edge from front to rear and an improved outer profile. Order 2 pieces per engine.

Complete rocker box set for Harley-Davidson Big Twin models with Evolution engine (Evo) from 1984 to 1999. The kit includes a three-piece rockerbox per cylinder head, all necessary gaskets, and mounting hardware.
These rocker boxes match the original Harley-Davidson design and are a direct replacement for leaking or damaged OEM parts. Precision manufacturing ensures a perfect fit and reliable sealing of the valve train.
Ideal for engine overhauls, maintenance, or repairs on Evolution Big Twin engines in Softail, Dyna, or Touring models within this production period.

Stock replacement rocker arm bushings for all 1966→ Big Twins and 1957→ Sportster models.

Stock replacement rocker arm bushings made from top notch Mil Spec bearing bronze for all 1966→ Big Twins and 1957→ Sportster models.

Replacement rocker arms for all Evolution and Twin Cam models. Comes ready to be installed.

The most common reason for noisy rocker arms is too much side-play. These shims are a fast and easy way to solve this problem.

If you are looking for something better than stock Evolution or Twin Cam style rocker arms, this is it! An economical solution for stock rebuilds, and mild performance upgrades. Forged from 4140 steel for greater strength than stock or cast steel rocker arms. In addition they feature the same .750“ long rocker shaft bushings as our S&S roller rockers do, for 50% more load bearing area than in stock and other aftermarket rocker arms. The valve contact tips are induction hardened for extended durability. Thousands of hours of engine testing have proved them to be superior to any non-roller rocker arm on the market. Recommended for cams of .585“ lift or less.

Attractively priced head bolt covers for all Evolution models 1986–up.

This smooth streamline device will keep your Twin Cam running cooler even on your second stop and go ride around Lake Faak in the midday heat. The Jims R & D department has come up with a fan system, that has been adapted from NASCAR race car brake coolers and which will drop your head temperatures by as much as 37° C. It mounts in the horn area, so the Jims team has designed a horn relocater hidden inside the housing. The fan can be installed to be turned on and off manually or it can be regulated by a thermostat controlled sensor. This kit is highly recommended for performance motors to help extend engine life. Complete kit includes high powered fan, housing, horn, hardware and all wiring, along with detailed instructions. Designed for Twin Cam models but can be fitted to other models with some fabrication.