There are two different cans you have seen injecting one thing or another into your pocket bike carb area. One is the popular boost bottle and then there is the Nos. The difference is the fuel/air mixture in the boost bottle comes from your bike itself and the Nos comes from an injected flammable chemical into your carb. Nos will provide you a better boost.
The Nos system described here is not actually a “Nos” system but will serve a similar purpose and is home made. It is simple to build and easy to install.
1. Solenoid from automatic sprinkler controller.
2. Spray can with flammable substance (starter fuel).
3. Zip ties
4. Spray can cap
5. 5ft of red electrical wire, 5ft of another color
6. Two screws
7. Super glue
8. Flexible tube 4 ft
9. Momentary switch
10. Crimp-able connectors or soldering iron
From the list above things like the tube will change setup based on where you put the spray canister.
Once you have assembled the system like shown in the picture (see link below) you will need to attach the solenoid to your battery and switch through a series circuit. There is no +/- on the solenoid just connect to any terminal. This is very easy to do and gives you the flex-ability to use different flammable sprays. One side of the tube attaches to the little indent in the stray button on the bottle and the other end goes into your carb, you can better your performance by adding a spray jet to the carb side of the tube. See the link below for the diagram.
Comment and let me know how it went.