731451 Easy Kit for 1990 2000 Evolution Big Twins Includes Hsr42 Ca

The Mikuni HSR42 Smoothbore Carburetor is widely regarded in the shop as one of the best performance upgrades you can give an Evolution Big Twin or Twin Cam engine. Featuring a 42mm venturi, it flows 20% more air than the older HS40, making it perfect for bikes with cams, big bore kits, or high-flow exhausts. The standout feature is the flat throttle slide assembly riding on roller bearings, which eliminates the turbulence caused by traditional butterfly valves and provides an incredibly light, precise throttle feel. This kit is designed to work with 1990 to 2017 style Big Twin throttle and idle cables and fits Dyna, FXR, Softail, and Touring models. It’s a proven way to achieve instant throttle response and a stronger overall powerband.