Changing or modifying Harley engine parts, exhaust systems, and intakes is an expensive exercise, and can be damaging to both the motorcycle and the wallet, if the whole package is not correctly tuned. Harley's exclusive use of fuel injection for 2007 and onwards has now made the dyno an essential tuning aid.
We chose the Superflow Cycledyn 250 Pro because of it's accuracy, and the fact that most of the major players involved in Research and Development of Harley related products also use this high end equipment. This dyno utilises an Eddy Current brake, coupled to the wheel driven roller, and controlled by the software, which allows us to apply a percentage load to the engine, or hold it at a specific RPM or MPH at different throttle openings. This is fundamental to being able to correctly modify the various "maps" within the stock ECM on the fuel injected models, and a great aid when tuning carburetted models, particularly with regard to ignition timing.
Since we only tune Harleys, our dyno also features a wideband lambda sensor for each cylinder (which measures the air/fuel ratio),linked into both the Superflow software and the Direct Link Flash Tuner engine management software that we run simultaneously through a custom built computer. All of this information, including data logs taken directly from the ECM, is displayed live on two 22" Widescreen LCD monitors mounted across the dyno.
Our Cycledyn is housed in a relatively large, custom built, sound proofed room, and stable temperature is achieved with a professionally designed and installed ducting system which utilises a high velocity 10hp intake fan and a separate system for exhaust gas extraction. The air is changed every 10 seconds.
Also built into the dyno chassis are 2 large fans, driven by the roller, which supplement engine cooling by blowing additional air across the cylinders and heads at road speed.
The automatically controlled carriage (which clamps the front wheel and locates the rear wheel in the correct position over the roller) is the extended version which allows us to accommodate longer Harleys such as custom built choppers and SuperTwins race bikes.
The whole point of this very sophisticated, Harley specific dyno facility, is to accurately mirror road conditions, and to this end we spend the bulk of the dyno time concentrating on part throttle driveability, not just the wide open throttle (WOT) runs that generate the numbers. A Harley that runs badly at part throttle openings (where it will spend most of it's life in modern traffic conditions) is no fun to ride. This is a big subject, so we will add more in the Tech Articles section.