Originally Posted by penguiness
For static timing:
Remove the timing cover (either have a replacement, be willing to drill holes in the old and have screws, or purchase a timing cover for a Sportster).
Lift the rear wheel off the ground.
Put the bike in 5th gear and turn the ignition on (don't start the bike)
Remove the timing plug (this is why you don't start the bike, you would have oil going everywhere through this hole wtihout a timing plug window - will get to this again in a moment)
Turn the back wheel until you are at the top of the compression stroke and then in very tiny increments (you will be convinced you did not move it at all) until you see the timing mark appear straight up. This is called "top dead-center". If you are not sure that you are at the top of the compression stroke you can remove the spark plug and turn the wheel until you feel air being pushed out the spark plug hole. Stop the very moment you feel air then go to the other side to turn the wheel for the timing mark.
I found it easier to raise the rear wheel just until it clears and then have something handy to use as a wedge to keep the wheel from moving after you find your exact spot.
Your ignition module (under where the timing cover was) should have the LED fully lit.
If not turn the module ever so slightly (clockwise) until it fully lights up. If clockwise does not work, try counter-clockwise.
Now, if you want to get the static as precise as you can:
You want to turn the wheel until just before the timing mark will enter the window at the top of the compression stroke. The LED should be off. Keep turning (such small increments that you will swear you never moved the wheel) and it should light up as soon as the mark begins to enter the window.
-- Edit: and no sooner!
Dynamic timing:
Get a timing plug window (American Sportbike part 5773 $5.95) and use a timing light. I honestly don't know of any other way to get this right and mess-free without that window. Someone else may have suggestions.