I noted on my byke (R1150RT 2001)that the current in one spark plug is opposite to the other one. In other terms I mean that in a spark plug (right) the direction of the current is correct from positive (central electrode) to negative (mass-ground) but in the other one (left) the direction is opposite and incorrect from negative to positive. Is that normal? Is the same in your bikes? Thanks a lot. Maurizio.