The Honda GL1000, an early Gold Wing, is a four-cylinder motorcycle with automatic timing advance. Timing the GL1000 means adjusting when the spark plug ignites the air/fuel mixture. This adjustment is made at idle speed. As the engine accelerates, the GL1000 automatically advances the ignition so the spark plug will fire as the piston is on its way up. However, by the time combustion tries to drive it down, it will be past top dead centre (TDC). Fortunately, you just have to set the timing at idle speed and the Gold Wing will take care of the rest.
Check and adjust the breaker points, if necessary. Refer to the owner's manual for specific instructions on how to locate the breaker points and how to make the required adjustment, if you aren't already familiar with how to do this.
Locate and remove the timing-hole cover. Viewing the bike from the left side, the timing-hole cover is to the right and below the right-most carburettor. Use a coin or something similar to remove it.
Replace the timing cap with Honda's clear cap. This allows you to see inside while preventing the oil from splashing out.
Remove the breaker points cover. It's on the left side, at the rear of the cylinder head. It is held in place by two screws, one at the top and the other at the bottom.
Connect the timing light to the "number 2" spark plug. It's the one in the front, on the left side. Most timing lights simply connect to the battery for power and then clamp around the spark plug wire. If this doesn't work, see the instructions for your timing light for the proper connections.
Start the engine and let it warm up.
Adjust the idle speed to 900rpm if it's not already there.
Use the timing light to view inside the timing hole. The "F" mark on the flywheel should line up with the notches on each side of the timing hole.
Adjust the timing, if necessary. Loosen the base plate screws -- the leftmost and right-most screws -- inside the points assembly. Rotate the base plate clockwise or counterclockwise until timing is correct. Re-tighten the base plate screws when done.
Increase the engine speed to 3,000rpm and maintain it. Again, use the timing light to view inside the timing hole. Two horizontal lines on the flywheel should align with the notches on each side of the timing hole. This means the automatic timing advance is working properly.
Stop the engine and recheck/readjust the breaker points for the "number 1" and "number 2" cylinders, if you had to adjust the timing.
Connect the timing light to the rear spark plug on the same (left) side. This is the "number 4" spark plug.
Repeat Steps 7 and 8. Note that the mark you will see this time on the flywheel is "F-2" and not "F."
Adjust the timing, if needed. This time, loosen the sub-plate screws (not the base plate screws) inside the points assembly. These are the topmost and bottommost screws. Rotate the sub-plate clockwise or counterclockwise until the timing is correct. Re-tighten the sub-plate screws when done.
Turn off the engine and recheck/readjust the breaker points for the "number 3" and "number 4" cylinders, if you had to adjust the timing in Step 14.
Reinstall the timing-hole cap and breaker points cover.