Could it be a mis- fire condition? might be worth wild to buy a set of standard plugs just to test it out. Actualy thats what I run all the time so they should be fine to test with, and for just a test the standard plug is cheap enough.
CBR929-jardine race can, down 1, polished frame and swing arm,wheels polished, HELI bars, Sargent seat, Puig racing screen
commuting on a VLX600 shadow for now, 60MPG!!! I punched out the baffles, so it has that V-twin snap and crackle that made H/D so infamous. Except this little scute is rice powered!!lol