Build the ultimate in a stock bike engine

One of the first things most people do shortly after they get their new motorcycle is start to modify the engine. In the time honor tradition of Harley-Davidson, the first thing to go on most bikes are the stock mufflers in an effort to improve the sound. This is usually the first in a long list of changes to the engine. Changes to the carburetor and ignition system also rank very high on the first to change list. These changes are done to improve the performance of the bike.

There are many companies out there that are competing for the dollars that Harley owners are willing to spend on their bikes. As an owner, you will be bombarded with a vast array of promises, claims and inaccuracies in an effort to get your money. Reading between the lines on many of the performance claims can be bewildering.

Does the Harley-Davidson world need another stock engine modification article? I decided it does, since the results obtained by the engine upgrades listed here provided significantly better results than those documented by the popular magazines aimed at the V-Twin crowd.

How to build your own Stage One engine

Stage One engines involve no internal changes to the engine. All modifications are made by bolt-on changes to external components on the engine. These components include air cleaners, carburetors, exhaust systems and ignition systems. No special tools or training is required to perform these modifications, although it is recommended you are comfortable working on your own motorcycle.

Over the past several years we have installed and tested many manufacturers components. The list of parts used in building the ultimate 'bolt-on parts' engine is the end result of this testing. The best and least expensive of the individual components was selected and tested as a single package.

All the parts used are readily available through your Harley-Davidson Dealer except for the spark plug wires, which can be ordered directly through Magnecor. The components have installed and tested on a variety of bikes. All components were installed according to the manufacturer instructions supplied.

The results of the dyno testing shows the power potential of the stock Twin Cam engine. Test results show engines producing over 70 horsepower and 72.5 ft. lbs. of torque. Dyno runs from multiple riders and bikes show the performance numbers produced where real. 

The results are due to a well matched set of parts being bolted-on to the engine. Seems that a little of that money the Dealers send back to Milwaukee is going into engine performance research.

The ability to create the same results with other manufacturers parts is a distinct possibility. There is an optional parts list of components that should perform as well as the parts tested. Please be aware that the parts listed in the Optional Stage 1 parts list have not been dyno tested unless otherwise noted.

Still not enough power for your needs? We decided to find out what happens when you take the Ultimate Stock Engine and make it a Stage 2 bike. There are more surprises ahead as we continue to step up the power in our "Ultimate Engine"  modifications series of articles.

The Parts List for Bolt On Performance

Dyno Tuning costs estimated at $150.00 plus tax.