I have carefully inspected the axle and adjuster cam on my '03 UC when changing out the rear tire and brake pads this past week. What I have found is that there is CONSIDERABLE slop (probably a 1/16" or 3/32") in the adjuster cam movement on the axle profile that fits through the cam. Attached is the section from my manual that describes the belt adjusting procedure. You can picture what I am describing by looking at the graphic on the right although it does not show the exact problem.
The problem is that the profile is cut in the threaded end of the axle where the cone nut tightens on the axle. This means that the adjuster cam is being turned by the profile that is cut in the threads where there is less metal to apply force to the cam. Consequently, the cam has compressed or deformed the edge of this profile on the axle threads. I went to the HD shop and bought a new cam hoping that it played a role in the slop I have noticed in this cam/axle interface. Unfortunately, this did not help. It is the axle and more specifically the threaded portion of the axle that is damaged. I have ordered a new axle from Zanotti's, but it has not arrived.
The consequence to this problem is that I do not think the axle is being pulled back evenly and in alignment as it is designed to do when taking out the deflection in the belt. After mounting the wheel and tightening everything up with the old axle and adjuster cam installed, I took the bike for a ride up to Lufkin and back. There was a discernible wobble although NOT severe around 65-70mph. I believe this is due to an alignment problem caused by the damage to the profile in the threaded portion of the axle where it makes contact with the inside profile of the adjuster cam. Poor design by HD. They should have made the profile on the axle in the non-threaded portion of the axle, and used a cone nut that had a relief to account for any protrusion of the non-threaded axle (or even just a 1/8" thick washer!!
I'll go out later and see if I can measure any misalignment of the axle.
TQ
The problem is that the profile is cut in the threaded end of the axle where the cone nut tightens on the axle. This means that the adjuster cam is being turned by the profile that is cut in the threads where there is less metal to apply force to the cam. Consequently, the cam has compressed or deformed the edge of this profile on the axle threads. I went to the HD shop and bought a new cam hoping that it played a role in the slop I have noticed in this cam/axle interface. Unfortunately, this did not help. It is the axle and more specifically the threaded portion of the axle that is damaged. I have ordered a new axle from Zanotti's, but it has not arrived.
The consequence to this problem is that I do not think the axle is being pulled back evenly and in alignment as it is designed to do when taking out the deflection in the belt. After mounting the wheel and tightening everything up with the old axle and adjuster cam installed, I took the bike for a ride up to Lufkin and back. There was a discernible wobble although NOT severe around 65-70mph. I believe this is due to an alignment problem caused by the damage to the profile in the threaded portion of the axle where it makes contact with the inside profile of the adjuster cam. Poor design by HD. They should have made the profile on the axle in the non-threaded portion of the axle, and used a cone nut that had a relief to account for any protrusion of the non-threaded axle (or even just a 1/8" thick washer!!
I'll go out later and see if I can measure any misalignment of the axle.
TQ