Tech Tip :WB E-Series Pipe Tuning Guide

Unless otherwise noted, it is highly recommended that you do not change the jetting after bolting on your new E-Series until you first try it with the standard and/or existing jetting, or the jetting that is noted in the instructions for your specific model. The E-Series Discs are designed to maximize flow without necessarily adding fuel (changing jetting). So many elements affect jetting such as alti-tude,weather conditions, engine and/or carburetor condition and cam timing etc. Even different riders will affect this. For instance,a novice who rides at lower throttle settings may notice more changes with the pilot and/or needle circuit. A professional using maximum throttle may not notice changes as much on the pilot and/or needle circuit, but will only be concerned with how it carburates on the main jet. Again, first bolt on the system and try it before making any changes.

Bolt the system on with the number of E-Series Discs supplied in the kit, then go out and ride it. Note the power and how it carburates compared to stock exhaust system. We have many cases where actually using less discs, increased the horsepower significantly.Your individual dyno chart for your model will show you the best overall combination to use.

All things being equal and in good working condition, a lean condition will be noted as a hesitation, increased temperature, loss of power and(or) back firing/popping on deceleration. A rich condition will be sluggish performance, black smoke, fouled spark plugsand(or) increased fuel consumption. Altering the number of E-Series Discs can improve and solve most of these conditions. Whenyou understand how they work in conjunction with each other, tuning becomes a very simple procedure.

In the simplest form, increasing or decreasing the number of E-Series Discs basically increases and decreases the size of the outlet hole. Adding Discs increases the outlet hole size. Subtracting Discs decreases the outlet hole size. In most cases, 4 Discs will equal the flow of a stock exhaust system. Equally, 28 Discs is the maximum number of Discs (provided the silencer core is large enough to handle this amount of flow). The core size will also affect the number of Discs you are able to fully utilize. You can note the core size in your particular E-Series by removing the End Cap/Disc assembly and measuring across the O.D.of the perforated core. Most E-Series come with a 2.0” round or 2.25”elliptical core.

By adding E-Series Discs, you are increasing the outlet area and thereby increasing: the powerband for more top-end power, the sound level and leaning out the carburetion. By subtracting E-Series Discs,you are decreasing: the outlet area and thereby decreasing the powerband for more bottom end or torque, the sound level and enriching the carburetion.

Remember, using more or less E-Series Discs does not necessarily equate to an increase or decrease in horsepower. Every engine has its “sweet spot”. And of course every person has their preferred powerband preference. The E-Series system was supplied with enough Discs for an optimum overall powerband response, sound level, and stock jetting. Additional Discs are available to provide you an even broader choice of tunability.

Above all, do not be afraid to experiment with the Discs. The new E-Series is fully tuneable. Adding and/or removing Discs can and does make a huge difference!

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