The other day I felt a loss of power so I opened the hood to seee what was wrong. I noticed the engine shanking quite a bit, and it sounded like it was missing. I pulled the 3 and 4 spark plugs. When I pulled 4 nothing happened to the sound of the engine. When I pulled 3 it changed very slightly. Then I swaped plugs to see if that was the problem, it wasn't. The spark to the plugs is also good. That lead me to think that mabey the valve clearences were off, they were perfect. The next thing i checked was my carbs. There was the same amount of gas in both bowls(40mm webers). Any help or ideas would be nice.