Proper Port Fitting Design

Due to the high velocity at the exhaust port, it is imperative that the flow be unobstructed. We have seen as much as a 5% loss of power for poorly matched headers and ports. To ensure proper flow, Burns has designed port fittings that properly align the exhaust header to the port. Also, the exacting dimensions of the fitting allows for better, more repeatable fabrication ensuring a proper fit on the motorcycle. On the Milwaukee 8 system, we have engineered a CNC machined fitting to improve the fitment of the pipes.

Stepped Primaries

By keeping the header size close to the exhaust port size, exhaust gas velocity is kept high at the port reducing the possibility of reversion. This is especially important with the unequal firing impulses inherent to the V-Twin single pin crank arrangement. Enlarging the tube with stepped pipes ensures that wall drag losses are minimized keeping the exhaust potential available for maximum power but also allowing for broad power band.

Collector Design

The 2-into-one collector helps minimize exhaust reversion while helping to scavenge the exhaust cylinder during each exhaust cycle. The efficient scavenging of the cylinder during the exhaust and overlap period allows for the maximum amount of air and fuel in the cylinder assuring maximum power.

Muffler

The Burns megaphone muffler provides the Pro-Stock appearance of the exhaust while maximizing performance and reducing the sound of the exhaust. The deep, mellow sound is a by product of the specially designed core perforations.

The small holes provide effective damping of sound waves while allowing for a smooth bore minimizing drag losses and improving power output.