Crossover Pipe (Balance Pipe)

A crossover pipe, also called a balance pipe or H-pipe, is a short section of tube that connects the exhaust header pipes of two cylinders, for example the front and rear cylinders of a V-twin or the two pipes of a parallel twin.

Linking the pipes lets exhaust pulses from one cylinder help scavenge the other, evening out pressure in the system. The result is usually smoother low and mid-range torque, fewer flat spots and a slightly deeper, quieter exhaust note. Many factory exhausts have a crossover hidden under the engine or behind a heat shield.

When changing to aftermarket pipes, keeping or removing the crossover can noticeably change how the engine pulls, and the fuel mapping may need adjustment. Check the joints for leaks, which cause popping on deceleration.