I've looked everywhere for an answer, but without success.
My problem is this:
When my v-twin, twin-exhaust motorcycle is at idle, there is a significant difference in the pressure experienced by a hand placed at the end of one pipe, compared with the other one.
Each of the two cylinders has TWO spark plugs, presumably to aid combustion.
What are the possible causes of the pressure difference?
Is there perhaps only one cause - that one cylinder isn't firing at all?