Dyno Testing

Dynamometer testing has become a big attraction at the annual J&P Cycles® Open House. A few times each hour, some lucky customer won a free spin on the dyno being run by Rob Creighton of Performance Diagnostics in Springville, Iowa. But you don’t have to be lucky to find out the fine details of your bike’s performance. You just have to be smart enough to find someone like Rob and be willing to part with $30 to $50 dollars before you spend a small fortune on performance parts that may or may not result in more horsepower.

Here’s Rob’s point of view on dyno testing:
There are many good reasons to test or tune a motorcycle on a computerized chassis dynamometer. First and foremost is the fact that dyno testing is the only way of determining if factors effecting overall performance such as cam selection, ignition timing, fuel/air ratio, exhaust selection, etc. are optimal. Performance is not just the amount of power or torque that a engine produces but also encompasses start ability, throttle response, fuel economy as well as the mechanical condition of the engine/drive train.

We normally see a average of 8-25% increase in horsepower and torque by optimizing the fuel/air ratio (jetting on carburetors or fuel curve remapping on fuel injection), tuning exhaust and setting ignition advance parameters. This is true even if the customer reports that the motorcycle is already running good. The reason for this is the fact that it generally requires a 10% change in performance to give the rider a real “seat of the pants” feel on performance gains or losses.

With the sensitivity and repeatability of the modern dyno, the experienced dyno operator can see changes as fine as a few tenths of a horse or ft lb of torque. This capability allows him to make small adjustments that result in maybe a percentage point or two of gain, but in combination with all the aspects of engine tuning add up to significant increases in overall performance. This cannot be accomplished any other way.

Dyno testing is also invaluable for providing a motorcycle owner with a performance “baseline” that can be used for comparison to determine the ongoing condition of the bike or if performance enhancing modifications are to be installed.

Performance part selection, such as what combination of cam, head mods, induction, ignition and particularly exhaust systems work well together can be best determined by using a dynamometer.

When properly performed, dynamometer testing does not in any way harm the motorcycle engine, drive train, tire etc., but can and does hurt the ego or pocket book of many motorcycle owners who have had various performance modifications installed that where not selected or tuned with the aid of a computerized dynamometer.