Abstract: A muffler for an internal combustion engine or the like having improved attenuation, minimal back pressure and minimal effect to column inertia through the muffler. The muffler comprises an outer housing and a first perforated tube insert extending from one end of the housing and terminating within the muffler. In another embodiment the perforated first tube includes a second tube insert abutting the distal end of the first tube in a continuous flow relationship therewith. The second tube has a smaller diameter than the first tube and includes at least one enlarged portion between its ends. Other embodiments are shown that include a combination of either the first and second tubes alone, a second tube with a plurality of enlarged portions between its ends, different sized enlarged portions between the ends of the second tube, various configured enlarged portions and at least two different sized perforations through the perforated tubes. A bracket is shown for attaching the tubes within the housing.

Abstract: An intake manifold for twin carburetors or twin air control throat bodies for a motorcycle or the like having one or more cylinders where the physical space is limited comprising a hollow central plenum chamber and hollow carburetor or air control throat body mounting flanges on each opposing side adjacently perpendicular to at least one side communicating with the intake track of at least one cylinder. In the case of two opposing cylinders, each cylinder communicates with the hollow central plenum chamber through opposing openings and the perpendicularly mounted carburetors or air control bodies. When a cylinder intakes a fuel mixture from the carburetors the fuel mixtures from each carburetor converge in the hollow plenum chamber where the direction of flow is turned toward the cylinder without physical impact with a physical structure during direction change. With the cause of air control throat bodies the air flowing through the manifold controls the flow of the air in the same manner as the fuel mixture.