How to Check the Timing on a Harley-Davidson Motorcycle Motor
Check the ignition timing every 5000 miles on your Harley Davidson. This is a fairly simply procedure, but it will save you headaches in the future. Bikes that are out of time will have some problems, and they'll only get worse. Take care of it now, and you won't have to worry about it. Checking the timing on your Harley is one of the easiest preventative maintenance items to take care of, next to changing your oil.
- Timing mark view plug
- Inductive timing light
- Hex socket to fit your timing plug
- Service manual for your model
- Internet access
Remove the hex socket timing plug; this is located on the crankcase. Set the timing plug aside, but don't lose it. You'll need to put it back when you're done.
Thread the timing mark view plug into the inspection hole where the timing plug used to be. Don't let the view plug touch the flywheel, though. Thread the view plug into the hole far enough that you can see the flywheel well enough to identify the marks you'll be looking for.
Look in the service manual to find the correct marking for TDC (Top Dead Center) on your flywheel. If the notations are not in the service manual, a quick online search will yield good results and most of the time will come with pictures as well.
Connect the inductive timing light. There are 3 hookups required. The first one clamps around the front spark plug wire, the second goes to the positive battery terminal, and the third one needs to be grounded somewhere on the bike.
Check everything again to make sure all vacuum hoses and wires are connected. Double check the connections at ground and at the battery.
Start your engine. Let the engine warm up to normal operating temperature. On non-California models the idle should be between 950 and 1050 RPM.
Aim your timing light into the inspection hole. The light will flash each time ignition spark is fired. Check to make sure that when the light flashes, the flywheel has turned so that the advance timing mark is in line with the timing light.
Set the idle with the idle adjustment screw. Turn clockwise to increase idle and counter clockwise to decrease idle.
Remove the timing mark view plug and reinstall the timing plug. Go ride!