The three primary components of a motorcycle’s engine are cams, valves and pushrods. All three parts work in conjunction and allow the engine to operate smoothly. As an 883 Evo Sportster owner, you should consider replacing your cams if the motorcycle’s engine power has diminished. You can also upgrade to larger, more powerful cams if you simply desire more power. Several different cam shaft size options are available to motorcycle owners.
1. Remove your motorcycle’s gas tank and rocker box tops according to your motorcycle owner’s manual. The rocker box tops are the top section of each head of the motor.
2. Remove the pushrods and the connected lifters from the rocker boxes by removing the retainer clips that hold the cover tubes — covering the pushrods — in place with a screwdriver. Pull the pushrods and lifters out by hand once you remove the cover tubes and number them with a permanent marker to make sure you place them back in their original position.
3. Remove the ignition parts just inside the outer cam timing cover from the right side of the motorcycle by removing the four screws that hold the cover in place. Once you remove the cover, remove the ignition parts and cam gears — located just inside the timing cover — by hand.
4. Install the new cam gears in place of the old ones. Turn each gear with your fingers to ensure they roll freely.
5. Check the end-play — the movement of the cam gears from side to side — by inserting a feeler gauge down through the lifter hole in the cam shaft. End-play clearance should be between 0.012 to 0.020 inches. Measure the clearance with your feeler gauge.
6. Reinstall the lifters, pushrods, rocker box tops and gas tank according to their original positions.