After purchasing a brand-spanking-new Harley, it's time to start doing what we do best and hot rod that sucker. Most of our Harley tech stories up to this point have concentrated on bolt-on parts for ...

Engine performance is like a complicated formula in which each individual part plays a role in the final answer. Some parts of the formula affect the final outcome more than others. The valvetrain ...

In racing, the valvetrain is one of the most highly stressed engine systems. High valve lift, high engine speed, and high spring pressures exponentially increase their demands on the lifters, pushrods ...