Harley Drag Pipe Tech Tips

Harley drag pipes are used on custom motorcycles.

Buying a Harley-Davidson is high on the list of many motorcycle enthusiasts, and the exhaust pipes are high on the list of things to be immediately replaced. Stock pipes are manufactured specifically for each model, but drag pipes are sleek, loud and — let’s face it — cool. There is a trade-off between performance and good looks, however, so consider some tech tips to ensure performance is not a casualty of the new drag pipes.

Torque Cones

Intalling torque cones in the head pipes will help performance.

Bolting torque cones inside the head pipes of the exhaust system will lessen some of the performance loss caused by drag pipes. The cones act as anti-reversion units that repel spent gas fumes while allowing less unburned gas to escape. Exhaust gaskets in the heads are first removed, the torque cones are inserted, then new gaskets are installed.

“Lollipop” Baffles

A home-made drag pipe baffle will lessen performance problems.

One way to enhance performance while not cutting too far into the sound levels of Harley drag pipes is to construct a “lollipop” pipe baffle. Instead of paying up to $80 for the part, this can be made at home for about $10. Weld a 3/4-inch washer onto the end of a 1/4-inch threaded rod or bolt and wind a nut onto it. Drill a 1/4-inch hole in each pipe about 1 inch from the end, insert the lollipop into the hole from inside the pipe, and put another nut onto the protruding end of the bolt. Set the lollipop at about 90-degrees in the pipe and tighten both nuts.

Carburetor Re-Jetting

Having a carburetor fine tuned and re-jetted will improve performance.

Always have the motorcycle’s carburetor fine-tuned when installing a new exhaust system. Although adding drag pipes can cost up to 10 percent of a Harley’s performance level, having the carburetor fine-tuned and re-jetted will considerably lower that percentage. Carburetor tuning can be done at home, although many motorcycle owners choose to have it done professionally. Jetting the carburetor is a simpler process, using screwdrivers and a purchased jetting kit.