What exactly is a Stage 1 upgrade for Harley-Davidsons? There are no hard and fast rules on what constitutes Stage 1 vs. Stage 2, 3 or 4, and everyone’s path in the pursuit of horsepower will be a little different. However, it is important to understand what other riders generally mean when they throw these terms around.

A  Harley-Davidson “Stage 1” horsepower increase involves getting more air and fuel through the motor without modifying the engine itself. For a Harley Stage 1 kit, you’re looking at a high-flow air cleaner to suck more air into the motor, an aftermarket exhaust (slip-ons are good, a full system is better) to move air out more quickly, and a new tune (courtesy of a Fuelpak FP3, Power Commander or equivalent) to match the increase in airflow through the motor with an equal increase in fuel delivery. Stage 2 means digging into the motor. For more info on Stage 2 and up, check out Engine Parts for Harley-Davidson.

Not sure how far to go? Just start with Stage 1 mods — you can always do more down the road, and that’s half the fun of owning a Harley. Most riders and tinkerers find that they are perfectly happy with the performance afforded by Stage 1 upgrades, and few dare to go any further while their bikes are still under warranty. Those who keep their motors stock long enough to see the first valve adjustment will often take the opportunity to throw in a new cam and pushrods (a perfect time to dip into Stage 2, if you haven’t felt the need for more speed before then!). It is easy to get caught up in a horsepower feeding frenzy, but remember there is plenty of street-able power to be had within the scope of even just Stage 1 upgrades, and that is where most (more-or-less) sane riders end up. But hey, don’t let a silly thing like sanity stop you — happy Harley upgrading!