Side gapping a spark plug
From Moped Wiki
Side gapping is a simple and easy way to make your bike perform better. A side gapped plug will give your engine a more complete burn for higher hp all over the power curve. However it may make your piston dome hotter.
To side gap a spark plug, simply cut the ground strap electrode as seen in the diagram. With a file or sand paper, make sure the ground strap doesn't have any sharp edges. Gap the plug between the closest two parts of the electrodes. Clean the plug thoroughly (you don't want any metal shavings in the cylinder area). Install the plug as normal and run the bike.