How to Replace Rings on a Harley

Harley-Davidson pistons use three rings to contain the compression loads and control the oil splash. The two rings closest to the crown of the piston are the compression rings. These are beveled so the expanding compression gases force the edge of the ring into tight contact with the cylinder walls. The oil control ring is comprised of three separate rings. It has a corrugated oil scraper ring sandwiched between two thin rings. Once the engine has been disassembled to the point where the cylinders are off and the pistons are exposed, the rings can be replaced.

Difficulty:

Moderately Easy

Instructions

Things You'll Need

• Dental pick set
• Piston ring set
• Ring compressor
• 3/8 inch ratchet with long extension

1. • 1

     Remove the old rings. Slide the ring in its groove until the ends are exposed. Hold one end of the ring with your thumb. Hook the other end with a dental pick and peel the end of the ring out of the groove. Continue peeling the ring until all of it is free of the groove, then slide the ring up and off of the piston. Repeat this process with the remaining rings.

   • 2

     Inspect the ring grooves once the old rings are out. Remove any carbon or debris from the grooves with the dental pick.

   • 3

     Install the new oil control ring set. Install a thin ring first by hooking one end of the ring on the top of the piston then wrapping it around until the whole ring is on the piston. Work the ring all the way down to the oil control groove. Follow it with the corrugated scraper ring and the other thin ring in the same fashion. Stagger the ends of the scraper and thin rings. Place the ends of the rings 120 degrees apart from one another.

   • 4

     Install the bottom compression ring. Ensure that the bevel side with the dimple stamped on the end is facing up. Hook one end of the ring on the piston and wrap it on. Slide it down into the second groove. Install the top compression ring the same way. Rotate the ring ends around until they are 180 degrees apart.

   • 5

     Open the ring compressor and install it over the piston. Close the compressor and tighten it with the ratchet and extension. Slide the cylinder onto the piston and allow it to push the compressor down and off of the piston. Open the compressor and remove it. Repeat for all pistons.

Tips & Warnings

• Never rotate an engine with the cylinders removed and the pistons still installed on the rods. The pistons can catch on the cases and damage the piston skirt and the cases. Trying to guide the piston into the block holes can be hazardous because the forces generated when the flywheel rolls itself over can create a severe pinch hazard.