How do you change spark plugs on a Harley Davidson sportster?

First set the gap for the plugs to 40/1000's. You can buy spark plug gap tools at any place that sells mechanical parts. Then pop the wire off the top of the plugs. Then you need a 13/16" wrench to take them out (counter clockwise). Then put the new ones in that are properly gapped. Tighten as much as you can with your fingers. Then once you feel resistance on the wrench give it just a little tightening (1.8 to 1/4 turn).

When you take the old ones out take a good look at them. If they're black and sooty your fuel mixture is too rich and if they're white it's too rich. Make necessary adjustments on your carburator.