Photographs courtesy of the Harley-Davidson Motor Company Archives

TwinCam.jpgIncreasing Harley performance is a topic that has seen much discussion in the form of books and other media. There are some major points to understand when approaching this subject. It is important to understand what kind of power your Harley needs and how to go about getting that power.

Performance

It is difficult to define performance, because everyone has their own opinion of what it means. You may just be looking for a little extra power and rumble to make your Harley pop, while someone else may want to increase horsepower for faster runs. Drag racing requires major upgrades to get the performance desired. That kind of adjustment can affect your engine and cause you problems later on. The majority of riders do not require modifications that are quite so extensive, and want to keep their Harley in the low to mid RPM range.

Power

There is a difference between torque and horsepower. Torque is the twisting power that gets you going. Horsepower is the spinning power that keeps you moving down the road. Deciding which kind of power you want is the first step in increasing Harley performance. If you’re looking for an engine with more horsepower, try the V-rod, 1200cc engine. The V-rod has better air flow, 4 valves, and dual cams, which allow the engine to spin faster. The twin cam, 1584cc engine will give you more torque, but lacks in horsepower. 

After deciding on an engine, you can gain about 10 horsepower by installing some slip on mufflers and a high air flow filter. This may cost you up and above $1000, but more power ain’t free.

The Basics

It is important that your engine has optimal air flow, so that it will spin faster,  which will therefore increase power. Engines that have better air flow, burn more fuel. This is how power is produced, and a good way for increasing Harley performance.

Another way to increase power is to turn the engine over quickly, which increases air flow and fuel. If you’re not getting the power you need in your engine, consider changing compression ratios to compress more air into the combustion chamber. Changing compression is not an easy job, but it can be worth it in the long run.

Usable Power

Target your power increase in the place you need it most. Most of your ride is in the 2,000-4,000RPM range, and that’s where the focus should be. Modifications done within these RPMs are much easier to do and are not as extensive. The 4,000-6,000RPM range is not used as often, so it doesn’t make sense to focus your modifications in that area.

Cams

Installing cams with more lift and duration can also increase Harley performance. The installation is not difficult and does not require replacing the heads. It is important to match the cams to the bike so that its not too much. Decide if you need a high end or low end torque, depending on where you do most of your riding. Choosing a cam that will give you more torque is  more economical way to add horsepower to your bike.

For many more ideas and best practices for increasing your Harley’s performance, check out the forums at HDForums.com!