A cam with a longer intake duration will reduce static compression pressure at low speed which in turn will tend to reduce low RPM torque. Changing cams is the easy way to more torque in the 2000-4000 RPM range. While bigger cams may have a higher peak horsepower, more conservative cams may feel stronger to a street rider because the max torque occurs at lower RPM. Street bikes will often perform better with a mild cam than more radical cams. It is important to note that too much cam sometimes results in poor low RPM power. Here is a short summary of modifications listed in the order of increasing cost and installation complexity. Almost every type of engine modification imaginable has been performed on H/D engines. To get the best cam for your bike all these factors have to be taken into account. Have the intake and exhaust ports been changed to result in better flow efficiency? Does the engine have higher than stock compression ratio to take advantage of a longer duration cam? Is the bike lighter like a Dyna or heavy bagger? Engine/Bike combination: This question relates to displacement (cubic inches), compression ratio, bike weight and what kind of cylinder head modifications have been done. In other words is your riding style conservative or aggressive?ģ. Type of riding: Do you spend a lot of your time riding two up on highway trips or is it more important to have the most power you can get. Primary application: Is the bike going to be used for all around street riding or is the goal to have an engine which is running at the maximum torque and horse power for track or drag racing?Ģ. The three questions to answer before choosing a new cam for your Harley Davidson® motorcycle are:ġ. Keep in mind that performance camshafts are usually chosen for the basic purpose of producing more power from your engine.

While there are no hard and fast rules for picking a cam for a specific application, some basic guidelines are worth considering. The question 'What cam should I buy for my bike?' is the one we often hear.

How harley twin cam works