That will go in next to the piston so you can keep the pistons on the rod . The rollers are easy (the first one anyway.) to install. they are held in place in pares by the retainers and white assembly grease. We kept the powerhead attached – tilted up the motor and turned it as far as it would go in one direction. Then we put half the rollers in the rod cap and held that against the crank. Then added the remaining bearings on the crank, lowered the piston & rod in and tightened the screws. Then we turned the motor in the other direction and did the other one. My job was holding the rod cap because , at the time, I had smaller hands.
