Engine

Active filters
- Bolt-on power: +40–50% on stock 107", 114" and 117" M‑Eight motors.
- Compressor and turbine housing with Garrett internals; plenum with integrated blow-off valve.
- Includes injectors, spark plugs, boost gauge with mount, oil feed/drain lines, custom cam cover, tune files, hardware and gaskets.
- Requires Thundermax ECM (sold separately). Does not fit Twin Cooled or non-removable fairing lowers. Offroad use only.
- Made in the USA.
Complete two-piston kit with precision-fit rings and enhanced pin oiling for dependable sealing and long life.
Forged, precision-fit piston kit with ArmorGlide® skirt coating and force-fed pin oiling. Value-pack includes two pistons, rings, pins, and circlips.
Forged aluminum piston kit with ArmorGlide® skirt coating; includes two pistons, rings, piston pins and circlips for a complete install.
Forged aluminum piston kit with ArmorGlide® skirt coating; includes two pistons, rings, piston pins and circlips.
Transparent cam cover that matches Assault series air cleaners and allows internal inspection. Made in the USA.
Transparent cover for viewing internal engine components. Matches the Assault series air cleaners. Made in the USA.
Transparent cover for viewing internal engine components; matches Assault series air cleaners. Made in the USA.
Designed for twin plug heads. Accepts .650"/10mm x 1.0 compression release valves. Sold each.
Adjustable front stabilizer link for HD Touring frames with reverse-thread rod end and ARP stainless bolts; available in black anodized, gold anodized, or machined finish. Made in the USA.
Mounts S&S E/G or Keihin CV style air cleaners to Mikuni HSR 42/45 carburetors. Made in the USA.