I tried to calibrate the carbs on my 1983 Goldwing 1100cc, cylinders 2 and 4 show readings on the gages but cylinders 1 and 3 have no readings what so ever. 2 and 4 spark plugs are dark almost black in color but 2 and 4 are clean and when I try to rev up the engine it wants to stall. I have set the valves before but have a tapping sound and a knock on valves 1 and 3 side, not sure what to do, I think this is a biggie?