... C. gold metal customer brand A7tc spark plug copper, alloy, platinum, iridium goldCeramic white or colored, heat resisting Metal appearance ... OIL CONTAMINATION AND DIRT.2. SET THE SPARK PLUG ONTO THE CYLINDER HEADAND, TIGHTENNING AND KEEP THE SPARK PLUG TO TURN 90°~180°. ... IT MANY TIMES BEFORE.3, MAKE SURE SPARK PLUG RIGHT INSTALLATION. SPARK PLUG HOUSING BREAKS IF TOO TIGHT WHILE MOTOCYCLE SHAKES ...