Some minor, simple repairs improve the performance of a Harley-Davidson motorcycle.
Harley-Davidson motorcycles direct from the factory are set to meet state and federal emission guidelines, according to the Harley-Davidson maintenance website. To achieve the ideal power potential, most Harley operators perform some tweaking to the intake and exhaust systems. Internal combustion engines need to breathe; fortunately, several performance improvements are possible to accomplish this and obtain an optimal power increase.
Catalytic converters, an emission device, and mufflers essentially create a “bottleneck” in the exhaust system of a Harley that restricts normal exhaust flow, according to harleydavidsonmaintenance.com. Harleys are equipped with a crossover tube designed to balance the flow of exhaust between the heads and thus improve performance. However, due to the factory exhaust settings, this becomes difficult and stressful on the engine. An after-market exhaust system known as performance or tuned exhaust, or high-flow, will allow the engine to breathe and perform more optimally. This upgrade is virtually essential to fine-tune the engine and obtain more ideal power potential.
Prior to tuning the carburetor, you must remove the engine after first emptying all fuel from the carburetor bowl. Simply run the engine for a short time after shutting off the petcock fuel valve. Also, you must remove the air cleaner assembly along with the backing plate. You may then safely remove the carburetor. Simply disconnect the fuel line, loosen the throttle cables and gently pull it away from the engine. To gain access to the mixture screw, you must first remove the soft metal plug covering it. Drill a hole into the plug and use an awl or pick to pry out the plug. To adjust the carburetor, use a small, flathead screwdriver to turn the mixture screw first in a gentle, clockwise motion to the closed position, then counterclockwise, opening it back up to just beyond your starting point. This will allow for a slightly richer idle mixture than the factory setting. Just reverse your removal steps to reinstall the carburetor.
Air Filter Replacement
Another tip for maximum power performance in your Harley is to install a higher-volume air filter. Your goal is to reduce the turbulence created when air passes through the air filter. Air that is less turbulent flows more easily into the carburetor. This increases air volume available for mixing with the fuel. There are two air filter design considerations to take into account. A intake design with a wider air opening, or a housing design more conducive to air flow, will both accomplish the goal of more air volume.