Ten years ago dyno tuning was the type of service that only race-oriented shops performed -mostly on Japanese and European sport bikes. But during the past 20 years we've seen performance enhancement (and the dyno tuning that accompanies it) become a lucrative commodity as the Harley-Davidson Evolution and Twin Cam 88 motors provided a perfect platform for performance massaging at all levels.

1. the stock ECM's (electronic control module s) memory or
2. the software for the accessory that piggybacks to the stock EFI system or
3. in the ECM memory of an aftermarket EFI system that replaced the stock unit altogether.

Yes, there are products that simplify EFI tuning by offering adjustability in only three broad areas of engine rpm. But with fuel-injected bikes having radical cams, big displacement or funky exhaust systems, you'll probably need the run ability that only a product with hundreds of circuits can offer.

Damn the EPA -Full Speed Ahead
With the EPA tightening the emissions limits to Tier I standards for 2006 motorcycles and Tier II standards for 2010 models, eventually most Harley-Davidsons -- make that most motorcycles -- will be fueled by EFI in the coming years. Carburetors may soon be as novel as a rotary-dial telephone.

Today's technicians must be able to diagnose EFI problems and tune EFI systems when significant changes are made to the engine s configuration (displacement, cams, compression, exhaust, etc.). That means you Ye going to need a chassis dyno with a steady-state load device and an air-fuel ratio meter  and an operator who knows how to use it. Unfortunately, knowing and doing aren't necessarily connected. Several years ago 1 visited 25 Dynojet dyno centers in preparation for the "How to Make Money with Your Dynojet Dyno" seminars I presented at the Dynojet Motorcycle Industry Performance Conference. I found only a few dyno operators using the dyno correctly. Later, as vice president of dyno sales at Dynojet Research Inc. 1 noticed that our tech support handled calls daily where the dyno operator was making mistakes. Hey, it's not easy, or everyone would be doing it. To properly operate a dyno and effectively tune EFI, technicians need to:

• fully understand the design and function of the engine, fuel injection, exhaust and ignition, be computer-literate,
• fully understand how to correctly operate the dyno, including its software, inertia load and steady state load devices, as well as its air/fuel measurement equipment (and understand how to load and unload the motorcycle on and off the dyno),
• be consistent and disciplined in the operation of the motorcycle so the test data is accurate and repairable,
• be able to interpret what the test data and air/fuel measurements mean, and fully understand the tuning product and software they're using to modify EFI fuel and ignition tuning.

By - Dave Koshollek