Harley Stage 1 Upgrade
Submitted by: Ken Mendleson
'How to get more power' is one of the most frequently asked question received about improving the performance of your Harley motorcycle. Some people are looking for more 'get up and go' from their stock engines, while others are looking for higher dyno numbers.
For those who have a stock or mildly modified Harley engine the answer is to move up to the next 'stage'... or a Stage 1 kit to be more exact. Before dragging out the catalogs and bolting on every gizmo claiming to make your ride go faster, let's start with the basics of a Stage 1 upgrade.
You've probably heard terms such as Stage 1, Stage 2, etc. Now depending on who you ask, a Stage 1 upgrade could be anything from an exhaust upgrade to a new carburetor. I'm going to base the term 'Stage 1' on what the motor company typically terms for this upgrade. With that said, a Stage 1 upgrade consists of the following:
1. Free breathing air cleaner.
2. Free breathing exhaust.
3. Rejetted carburetor or remapped EFI.
4. Upgraded ignition (if require*).
There is probably no greater beginning upgrade you can make than Stage One, which consists entirely of bolt-on parts. If you want you can take this upgrade one step at a time however, I recommend going in the order listed above if not all at once.
Free breathing air cleaner. This is the simplest upgrade to perform for most Harley owners. Depending on your budget this ranges from changing the air cleaner to a K&N or other element, to installing higher end air cleaner assemblies like Forcewinders and Hyperchargers. At minimum you need to let your engine breath by changing the stock air cleaner. You don't have to spend a fortune but pick something that fits your bike well. If your plan is to keep the look of your current cover assembly go with Screamin' Eagle or Arlen Ness 'Big Sucker' assemblies. These allow you to use your stock cover but the difference over stock is amazing.
Free breathing exhaust. As with the air cleaner this upgrade can be simple or extreme. Many choose to keep their stock pipes and go with slip-on mufflers. These are easy to install, maintains a stock look, and adds plenty of performance. Popular slip-on models include HD Screamin' Eagle II, Cycle Shack, Bubs, and Khrome Werks to name a few. My favorites are the ones from Khrome Werks and Python, but the others are just as good. If your budget is slim (join the club) then try buying used like on Ebay. There you will find many models from people who are upgrading to full exhaust systems or another flavor of the month. I've found the best deals on slip-on mufflers on Ebay that were sometimes less than HALF of what the item would cost new. To read more on other exhaust systems check out the Harley Performance Exhaust page.
Rejetted carburetor or remapped EFI. Once your engine is breathing it's going to need to do a better job at providing a stable fuel mixture. Your carburetor or EFI will need to be corrected to compensate for how differently the engine now breaths. On carbureted models this means rejetting. This is a simple operation that is explained in detail under Harley Carb Jetting. Various kits are available to recalibrate the carburetor including those offered by Dynojet, Yost, and the Stage 1 Carb Kit. EFI models are another story. Fuel injected models use a programmed map to regulate how much fuel is to be delivered. Since you have changed the way the engine breaths, those instructions may not supply the proper stable fuel mixture under all conditions. Granted your bike will still run, but the only way you are going to get the most out of your EFI bike is to have it remapped by a qualified shop. There are simple ways to do this yourself using devices like the Power Commander or SE Race Tuners kit.
Upgraded ignition*. I placed a '*' next to this last item because under certain circumstances you can go without this upgrade and still accomplish a Stage 1 upgrade. Particularly with Twin Cam models, which already use a single fire ignition. Aftermarket TC88 ignitions offer higher rev limits and altered advance curves but unless you plan on hitting 6200 RPM (you shouldn't anyway!) then stock is just fine. Evo engines and earlier models have Dual-fire ignitions and can really benefit from the single-fire upgrade. Dynatek's very popular DYNA 2000 ignition was previously reviewed and is an excellent performance upgrade for pre-1999 Evo engines.
That's really the core to performing a Stage 1 upgrade. The next step is Stage 2 which includes installing a performance cam, and Stage 3 (and 4 and beyond) include upgrading your heads, big bore cylinders, and stroker kits. Before tearing down your engine or spending your hard earned cash on modifications, try your own Stage 1 upgrade as described. You may be surprised just how much power is lurking within your stock Harley engine.
Enjoy the Ride!
About Author: Ken Mendelson is the author of many articles on Harley-Davidson motorcycles and performance tuning. In addition, Ken runs the popular Harley web site Harley-Performance.com
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