How to Get More Power Out of a Harley Road King

by TJ Hinton
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Between the components offered by Screamin' Eagle and the aftermarket, there are numerous performance-enhancing products available for the 2014 Harley-Davidson Road King. The procedures and components have varying degrees of complexity and price, so you have options to fit your individual abilities and budget. Generally speaking, most horsepower gains are achieved by increasing the amount of air-fuel mixture moving through the engine, with smaller gains possible by using a programmable electronic control module and other more traditional methods. Harley beefed up the power for the 2014 Twin Cam 103 engine used by the Road King, but modifications will increase passing power on the highway and improve your acceleration off the mark around town.

Intake and Exhaust Systems

Lowering the resistance in the intake and exhaust systems is one of the least-invasive procedures you can perform to gain immediate horsepower and torque increases. Low-restriction filters, intake components and exhausts are available through Harley, as well as performance aftermarket companies such as S&S and K&N. These modifications will allow an increase in the volume of the exhaust note, and while they are generally street-legal, the decibel level of your exhaust note may not be in all areas. Check for relevant laws in your area before making these modifications.

Internal Modifications

Increasing the displacement of the engine by boring out the existing cylinders or installing larger cylinders and pistons will give you a significant power boost. Kits are available through Screamin' Eagle, S&S and other performance part manufacturers. Performance cams are often part of the kits, but more radical cams are certainly available. Your 2014 Road King comes equipped with slightly hotter cams than previous years, so swapping the cams should not be high on the list of priorities as far as how much bang you can expect for your buck. Since valve-to-piston clearance becomes an issue with the more radical cams, unless you are experienced in engine building, consult with a professional for guidance through the cam selection process.

Electronic Control Module

Performance ECMs give a moderate boost to performance and are available with a range of capabilities, from simple ones with a fixed power curve and rev-limiter, to fully programmable modules. The best ones can be patched into a laptop or PC and, using the proprietary software, dialed in to the last tiny detail. Screamin' Eagle and the Dynojet Power Commander are two of the more popular ECM brands.

Other Considerations

The more traditional methods of increasing performance, such as porting, polishing and the use of performance headers will help to coax a modest amount of power from your engine. Performance electrical components are easy to install with non-invasive procedures. High-output coils, spark plugs and spark plug wires help to increase flame-front propagation and more complete combustion of the charges as they come through the combustion chamber, leading to a minor performance increase with a small increase in mileage.

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