If you have a Hero Impulse are aren't happy with the power that the 150cc engine outputs, an easy way to fix the problem is to simply let more air into the engine. Hero has set up the engine for better mileage which means it's basically choked and gasping for air all the time.
It's quite easy to make the engine breath more easily. Remove the side panels and then the seat to expose the air box. You can start by removing the rubber snorkel protruding from the top of the air box. This will increase the air entering into the air box, but only marginally. To let more air in remove the lid of the air box completely to expose the air filter. After doing this you should experience a noticeable increase in power. This is because the engine sucks in more air due to lesser restriction and along with it more fuel. Your mileage will drop quite a bit but the power will increase significantly. The engine sound will also increase and that's largely due to the greater suction, not the exhaust.
You will not need to mess with the carburetor. The stock 132 main jet is already large enough to handle the increased air intake. You are essentially burning more fuel in the same engine, which yields the additional power.
This is a basic and simple mod that can be done by anyone. For more advanced engine tuning you may need the help of someone who knows a whole lot more.
