Indexed Spark Plugs align the open end of the electrode towards the intake port.
The hottest flame meets the new fuel charge for a performance gain, increases h.p, fuel mileage, & plug life.
This is a speed secret car racers have used for years. You simply mark the electrode side of the plug with a magic marker on the porcelain. You then shim the plug with washers to align the electrode towards the intake port. Fits 14mm plugs.
4 washers in each kit.
red= 1.68mm Blue= 1.23mm Silver 1.04mm Gold= .91mm
Major two stroke tuning secret!