I just saw them on partsnmore.com, a bit more expensive but I have ordered from them before and had a good experience. This page SHOULD bring it up but if not, go to cb750k and click chassis on the left and it should filter it. A bit more expensive at $35 but shipping isnt TOO bad, 8 something.
http://www.partsnmore.com/parts/honda/cb750k/?filters[category]=chassis&filters[page]=2
OH, have you checked the tension on your spokes? If they are of, it could cause a wobble but tar snake, raid groove, and depressed wheel tracks can all cause crap like this. I HATE rain grooves.
The ride IS the adventure. The destination is just to get gas!