Why there is a firing sound from the silencer of a bike?

On domestic motorcycles, there is often a problem associated with the appearance of loud sounds in the muffler. Even drivers of foreign vehicles often suffer from “machine gun bursts” that accompany a sharp increase or decrease in speed. Getting rid of this nuisance can be quite difficult. However, if you understand why a motorcycle shoots at a silencer, you can eliminate loud noises that violate public peace.

What is affected by the shots?

Problems in the ignition system do not bode well. In such a situation, with prolonged engine operation, not only the aesthetic impression may deteriorate. Contamination of the carburetor or low-quality fuel will eventually disrupt the compression of the cylinders, which in turn will lead to engine failure.

To understand why a motorcycle shoots at a silencer, you should check the problem areas. Here are the possible ones:

– non-tightness of the pipes that can suck in air, or the exhaust tract;
– spark plug malfunction;
– contamination of air filters or carburetor;
– the difficulty of fuel supply;

However, the problem may also be in the speed limiter of the racers. Candles are not constantly charged, which is why most of the mixture goes straight into the exhaust system, where it feeds on hot metal and ignites, creating a loud bang.

The essence of the problem

The loudest pops in the muffler of two-wheeled vehicles are most often heard when a depleted mixture is fed into the engine. The reason for its formation may be the use of low-quality gasoline saturated with water and non-flammable impurities or incorrect adjustment of the intake system. The fuel-air mixture burns only partially – its remnants splash out into a hot muffler, where they explode with sharp unpleasant sounds. A symptom of the depleted mixture is the popping “bursts”, which increase with increasing speed.

In powerful motorcycles, the exact opposite problem is more common, associated with the supply of an overly enriched mixture. For its burn, there is not enough oxygen, which leads to the settling of gasoline condensate on the walls of the muffler. When the “critical mass” is reached, the fuel ignites outside the engine, resulting in one loud bang. If the problem is not fixed, within 1-2 months, the contents of the silencer will simply burn out, and it will turn into a “straight line”.


The easiest way to get rid of pops on a carburetor motorcycle is to simply move the needle valve to another position by changing the degree of saturation of the mixture with gasoline.

The carburetor in a motorcycle

It happens that a motorcycle shoots at the muffler and carburetor — this is often found on domestic “Urals” and imported choppers with a large cylinder volume. The problem lies in the clogging of the fuel-air mixture at the intake. To eliminate it, it is worth changing filters and sealing gaskets, as well as checking how tightly the pipes fit the receiving fittings, and whether there are any large cracks in them.

Very often, pops appear after replacing the muffler with a non-standard one or cutting holes in it to eliminate resistance to exhaust gases. Especially unpleasant sounds are manifested when installing the “direct current”. The reason is the creation of a strong vacuum, which leads to depletion of the fuel-air mixture. Powerful imported motorcycles often use an exhaust afterburning system that reduces their toxicity — after removing the standard muffler, its operation becomes audible. To eliminate shots after changing the silencer, it is necessary:

– Reconfigure the carburetor or rewire the control unit.
– Install filters with different bandwidth.
– Turn off the exhaust afterburning system.

For sports motorcycles whose engines run at high speeds, the problem with shots may be related to the speed limiter or the crankshaft speed. When a certain indicator is reached, the fuel supply may remain unchanged for some time, while the number of flashes decreases. Accordingly, a huge amount of gasoline gets into the silencer, which explodes with a staccato sound, forming a “machine gun burst”. It can be heard especially well when the gas is discharged after active acceleration. It is impossible to eliminate such a problem without reducing the resource of the motor — you have to change your driving style so as not to annoy yourself and others with unpleasant loud claps.