Brand New J and JD Cams by LINK Engineering Made in the U.S.A
The bushings on this new cam have only been lightly reamed to allow it to slip onto the inspection fixture and may require final sizing before installation.
Below is an excerpt from page 20 of the Harley Davidson publication, "Motor Repair Manual for the Guidance of the Motorcycle Repair Man", copyright 1918. As it states, the running fit of both the cam followers as well as the cam on the pins is a "free running fit, which translates into 0.0005" loose. You, or your motor builder, may have to hone or ream the bushing for final fitment. If reaming, it's advisable to do it on a decent drill press or a mill for accuracy. You should also enter from the gear side to maintain concentricity of the gears pitch circle to the centerline of the hole. The pin in your particular motor may however be slightly worn in which sizing may not be necessary. If the cam slips on to the pin and spins freely with no bind as is, then re-sizing should not be necessary.
To Inspect, Adjust, or Replace Secondary and Roller Arm Studs
1. Inspect the studs to see whether or not they are loose or worn. To test either stud to see if it is loose, strike it lightly with a small hammer.
A loose stud can be felt and will make a dull thud when struck.
If a loose stud is found, tighten it securely as explained hereinafter.
2. If the stud is tight, inspect it for wear. Try the secondary gear on the secondary stud, and both inlet and exhaust roller arms on the roller arm stud for shake.
These parts are assembled with just a free running fit, the inside diameter of the roller arm bushing or the hole diameter of the secondary gear being 0005 inch larger than the diameter of its respective stud.
Secondary gear studs are ground to ½ inch diameter, while roller arm studs are ground to 7/16 inch diameter.
3. If the exhaust or inlet roller arm or the secondary gear clears its respective stud by more than 0015 inch, the studs or stud plate assembly, secondary gear, or the roller arm bushings should be replaced. Too much clearance at any of these places reduces valve lift and delays valve action, cutting down the efficiency of the motor and also making the motor extremely noisy.