Vance & Hines Dyna Double Barrel exhaust system improves performance and horsepower over the stock exhaust system.
Harley-Davidson motorcycles and Vance & Hines exhaust systems are a perfect marriage of technology. While the Dyna motorcycle is near-perfect for many riders — right out of the factory box — installing a Vance & Hines Double Barrel exhaust system increases performance and horsepower, imbuing the exhaust system with the famous Vance & Hines throaty, signature tone. Carefully follow the instructions packaged with your new Vance & Hines exhaust system. If in doubt about any of the do-it-yourself steps, consult a Harley-Davidson technician, before proceeding.
Stock Exhaust System Removal
1. Remove the motorcycle’s seat and unplug the rear oxygen sensor connector. Remove the two bolts holding the rectifier onto the front of the frame near the front tire. Open the plastic cover and unplug the front oxygen sensor connector from its harness.
2. Remove the cable tie holding the wire to the frame and remove it from the motorcycle. Loosen the heat shield clamps on the front and rear head pipes. Remove the two cylinder exhaust port flange nuts from the head pipes located at the cylinder head. Remove the complete exhaust system and set aside.
3. Remove the mounting bar and the studs in the transmission cover, setting aside one bolt which will be re-used on the new exhaust system. Remove the left bolt below the transmission cover. Position the mounting bracket over the mounting location to determine which bolts to remove. Install this bolt in the empty hole at the top.
4. Remove the flanges and circlips from the stock system using snap-ring pliers. Remove the stock oxygen sensors to use with the new Double Barrel exhaust system.
Installation of Dyna Double Barrel Exhaust
5. Attach the supplied mounting bracket to the transmission, using the stock bolt in the top hole. Install two hex bolts — 5/16-inch and 1-1/2-inch — and the supplied 5/16-inch flat washer into the remaining holes, following the diagrams in the Vance & Hines instructions. Install circlips and flanges — which you have set aside from the stock exhaust system — onto both new head pipes. Apply a dab of anti-seize compound to the threads of the oxygen sensors and install them into the new head pipes.
6. Remove the head pipes and heat shields from the protective packaging, and place each heat shield on a non-abrasive surface such as a blanket or soft carpet. Mark the outside edge of each heat shield with a felt tip pen to indicate the location of the hose clamp mounting clips, as per the diagram in Vance & Hines instructions. Install the heat shields onto the header assembly. Install the hose clamps, taking note of the clamp screw head direction for later adjustment, if required. Install the head pipes — starting with the rear cylinder — into the exhaust ports, using the stock flange nuts you have set aside from the stock exhaust system. Do not tighten.
7. Slide the supplied nut plates inside the bracket that is welded to the backside of the muffler body. Attach the head pipe to the mounting bracket while holding the nut plates in place, using the supplied flange head bolts; do not tighten.
8. Tighten the exhaust port flange nuts and flange bolts to secure the muffler bodies to the mounting bracket. The ends of the muffler heat shields must match up when viewed from the top and the right-hand side of the motorcycle, as per the diagram in the Vance & Hines instructions; the muffler heat shields must extend beyond the muffler body by 1/2-inch, when measured at the bottom edge.
9. Feed the front oxygen sensor wire through the frame and into the plastic holder on the frame, and plug the sensor into the stock wiring connector. Snap the plastic holder closed, to secure the connector. Insert the toothed edge of the wiring holder into the slot in the frame and re-install the rectifier. Tighten both bolts. Install a new cable tie to hold the wires onto the frame in the same location as the original exhaust system. Feed the rear oxygen sensor through the frame and into the compartment under the motorcycle seat. Plug the sensor into the stock wiring connector, and finally, re-install the seat.