Well there is a number of options starting from a simple rigged setup to a more official, albeit expensive, approach. If you use any of the methods below I definitely recommend taking extra precautions because music as we all know can be quite distracting during a motor vehicle so extra precautions needs to be taken during a bike. So knowing that let's take a review of our options: Air filter is blocked so there isn't enough air input. There is a downside to motorcycle sprocket, like idling air inlet congestion, then this air input isn't enough. The oil level of float chamber is simply too high, some gasoline go directly into the cylinder without atomization, which will cause incomplete combustion. Main orifice wearout seriously and then the fuel injection from primary nozzle increases, that can cause incomplete combustion. Heating automatic valve is start position along with the enrich valve is not closed automatically, that will caused a wealthy mixture. Carbon deposit in muffler, exhaust jam, waste gas stay in cylinder, that can caused incomplete combustion then black smoke. To create a social world before photography, we might must create a world without picture IDs; without portraits of ordinary people; one without pictures as souvenirs of travel; one without celebrity pictures; one without advertising photographs; one without X-rays or views of outer space; a world without views of foreign and exotic peoples; one without pictures of sports, wars, and disasters; the other when the great masses of people had no approach to visually record quite events of their lives.