Three Rivers Harley-Davidson®
1463 Glenn Avenue, Glenshaw, PA 15116
​Dyno Tune and FAQs

​Dyno Tune and FAQs

A Dyno Tune is where you make adjustments to your motorcycles. Key aspects such as: ignition, fuel level and air supply.  With these adjustments, your bike will perform at top notch with achieving highest horse power levels and showcase some serious torque all while maintaining optimal air fuel ratio.

For the most part any motor that has had changes made to the air filter system, muffler and/or exhaust headers most likely will need to be tuned for the components added or changed. It makes no difference if your bike is normally aspirated or injected. Both can be dyno tuned.

We have a credible Service Department that has been trained and authorized to run the dynamometer (Dyno). These technicians have been trained in all of the latest and new software options available.

The time may vary depending on your Harley-Davidson® motorcycle.  All Harley-Davidson® motorcycles are built differently so depending on your type of engine, it may take longer than another type of engine. We do not charge more than four hours of service labor for normally aspirated fuel-injected (two hours of service labor for normal carbureted) Harley-Davidson® motorcycles.

There are a couple of options available for your motorcycle.

  1. Power commander
  2. Screamin' eagle race tuner
  3. TTS Master Tune

Metric bikes / sport bikes are limited to the power commander.

The power commander is a separate unit that is placed in line between the bike’s wire harness and the onboard ECM. This unit tells the original ECM what changes to make in fuel supple, timing, etc., to achieve the desired and expected results. It acts like an interpreter from one language to another. This actually works very well while leaving the factory ECM unchanged.

The second option is the screamin’ eagle race tuner. This is a program that connects your bike to the computer with a black box, called a key. This key is married to your bike only, and cannot be used on any other bike. This key is the only access you have to your ECM for mapping. This program actually re-maps the factory ECM. This is a good option for a Harley® with space problems under the seat. This option is the most costly and takes the most time.

Why is a custom map better than a map downloaded off of the internet? There are differences in each motorcycle, even between the same make and model side by side. Maps downloaded off the internet, or installed in a new piece of performance hardware are designed to get you close for your bikes modifications, but that doesn't take into consideration altitude, ambient temperature, humidity, location, or the differences between each bike. By setting the air/fuel ratio for your specific motorcycle, we can get all your bike has to offer in drivability and horsepower.

Every dyno reads a little different, different brands read differently. Temperature, altitude, and humidity can all play a role as well as software differences from dyno to dyno. The only thing to really worry about is the A to B changes on the same bike, same dyno, and same day.

When lead was in our gasoline, you could read the mixture by looking at the spark plugs and the exhaust pipe for the rich tan color that spelled a good running motor. Today there is no lead in gasoline so all we have coming out the pipe that deposits is carbon. Carbon is black and builds up like soot on the exhaust pipe causing one to think their bike is running rich when in fact, it may be running lean.

Horsepower is top speed and torque is what gets us there. Air fuel ratio is how much air and fuel are mixing and entering the combustion chamber. This is how rich or lean the motor is running. Either end of the scale will cost you power, torque, economy, and efficiency. If you get the balance too far out on the lean side, damage can be done to the motor. If you get unbalanced to the rich side, you can foul spark plugs, dilute your oil with gasoline, and generally cause a noticeable reduction in performance.

All motors produced today that are in legal production have to meet federal EPA requirements and are generally on the lean side of the scale. Changing exhaust systems, mufflers, air filters, carburetors, and sometimes-even spark plugs affect the way a motor performs. While making these changes may seem like the thing to do, one can end up with problems if these are not done properly.