the rotor phasing does not change with mech adv/RPM and that (only) was our point of contention. with a functioning mech adv system (slots/weights/springs) with the vac can capped: if the rotor is pointing dead on at the center of a cap terminal at any RPM which is the RP then any amt of RPM/mech adv change will not change the RP (it'll still be dead on) or a bit behind or ahead whichever you started with). this is the hardest ten bucks I've ever earned in my life! (& I ain't collected yet). EDIT P yes make sure your mech springs are functioning & drill the hole in the cap as this is ONLY about if the rotor moves or does not move with the light on it as you rev it & get into the springs (advance)