The tough riding I'd been doing off road, or should it be called, Off Highway Vehicle legal road has caused a split in the drive sheave. Amazing the belt still continued to work but was half way around splitting off completely one side of the v-belt groove.
I split the zinc/aluminum cast metal drive pulley I attached to the rear wheel spokes of my motor bike. So since it is not available since I last recall during the 1970's the same kind of pulley with spoke arms and made of steel, I went to get a Whizzer sheave clone from Ebay.
It has some rough edges on the thread clamps and also the seam in the press sheave, but looks like rather than return it should be easy enough a fix.
I'm just going to see that the seller has to say, as it is return shipping cost of buyer even when it is defect or workmanship. It is the only thing available, but looks like a good deal even with this happening.
A new heavy duty wheel with 12 gauge spokes is on the way to me and will have it back and running again soon with a new belt for the larger sheave diameter.
MT
PS: I think the threads on the sheave clamps are akin to Stover Nuts. All Metal Locking Nut that deform a portion of the threads intentionally. No instructions mention this, but this is probably the case. The seller did not mention this as was probably unaware of what he was looking at of the pictures I took that I sent him. Without my request I have been sent additional hardware and expect it to be the same.
http://motorbicycling.com/showthread.php?t=29678&page=16