420/500/520 Primary (clutch) Reduction 80%

  • Sale
  • Regular price $950.00
  • 3 available


The website automatically displays the more expensive billet basket option, use the option box above to choose the cheaper cast basket option.

**Price includes a $175 core charge on the aluminum clutch basket. Please send in your stock basket and include a copy of the original purchase receipt for the $175 core refund.

This is our billet 80% (actual 83%) gear reduction for foot-shift and standard ES machines. DOES NOT FIT DCT (AUTO+ES) MODELS! This reduction requires extra case clearance/cutting around the change clutch basket. Our stiffer stage 2 clutch springs are necessary with this size reduction. The stock clutch springs do not provide enough clamping force to hold the extra torque produced from the lower input ratio.

**ES models will need an ES module to prevent electronic shift issues. Springs, ES modules and seal kits are located in the 420/500/520 sections and "Parts" section of the site. Pic is an example and may not show correct size.