Tech Pages - CAD Parts diagrams - Customs by Ripper
This page has custom parts dimensions as well as some stock dimensions, templates, etc.. There may not be a lot yet, but I'm working on it. These dimensional diagrams were drawn up by Bob Oiler of Ohio Choppers
Here's a diagram for neck cups for a Harley Big Twin frame
Here are dimensions for a set of foot pegs
Here are dimensions for 39MM trees in a Wide Glide width.