How to Check the Timing on a Harley-Davidson Motorcycle Motor

by TJ Hinton

Harley-Davidson recommends that you check the 2002 Sportster's vacuum-operated electrical switch and petcock vacuum hoses for condition and proper installation before starting the timing procedure. You can damage the engine if the VOES is not connected or not functioning properly. Replace any hoses, or the VOES itself, if you find them to be bad. Use caution when using the clear timing plug. It is easy to damage it during the process and you'll have to repair it before using it again. It should be close enough to the flywheel to wipe most of the oil off the flywheel, but not so close that it actually contacts the flywheel. Be gentle with the plastic plug when you are turning it. It is rather fragile, and if it breaks it can fall into the crankcase, necessitating a full engine disassembly to remove it.

1

Support the rear of the bike on a bike jack so that the rear tire clears the ground. Check the position of the jack on the right side of the bike to ensure that it's bearing on the frame member and not touching the exhaust pipe. The pipe hangs lower than the frame and you can damage it with the jack. Place the transmission in fifth gear and turn the ignition switch to the "On" position.

2

Remove the spark plugs, using a ratchet and socket. Remove the timing plug, using a ratchet and Allen driver. Slowly rotate the rear tire by hand and watch for the front intake valve through the front spark plug hole. Once the valve opens and closes, start watching for a vertical line on the flywheel through the timing hole. Stop the rotation when the mark is centered in the hole. Rotate the engine in the normal direction of rotation and never back the engine up. If you pass up the right spot then you have to go around again.

3

Drill out the decorative timing cover rivets, using a drill and 1/8-inch drill bit, then pull the decorative cover out of the recess. Using a Phillips screwdriver, remove the timing cover backing plate screws, and remove the plate from the recess. Loosen the timing plate screws slightly, using a flat-head screwdriver, and leave them tight enough to provide a little resistance. Rotate the timing plate in small increments and stop right at the point that the LED on the timing plate comes on. Tighten the timing plate screws securely.

4

Install the spark plugs and torque them to 11 to 18 foot-pounds, using a foot-pound torque wrench. Lower the bike and rest it on the jiffy stand. Place the transmission in neutral. Install the clear timing plug in the timing hole.

5

Install the inductive pickup on your timing light over the front cylinder spark plug. Connect the positive clip to the battery positive post and connect the negative clip to a convenient ground. Start the engine and aim the timing light through the clear timing plug. Watch for the pair of dots that mark the advance timing position. Loosen the timing plate screws and adjust the plate until those marks appear centered in the timing hole. Tighten the timing plate screws securely. Kill the engine and turn the ignition switch to the "Off" position.

6

Install the timing cover backing plate and tighten the screws securely. Install the decorative timing cover, using rivets and a pop-rivet gun. Remove the clear timing plug carefully, then install and torque the original equipment timing plug to 10 to 15 foot-pounds, using a foot-pound torque wrench and Allen driver.

Tip

  • check If you scratch the clear plug on the flywheel, then you will have to work those scratches out by sanding the plug down with fine, wet-dry sandpaper. Use liberal amounts of water to keep the paper from clogging. Work down from 220-grit paper to 15-micron paper, and finish with jeweler's rouge.

Items you will need

About the Author

TJ Hinton trained as an auto mechanic at Mississippi Gulf Coast Community College and then later graduated from MMI as a certified motorcycle mechanic . He's also worked for 20+ years in home construction, remodeling and repair. His articles appear on InternetAutoGuide.com and TopSpeed.com.