So I had a nice natter
with Denis Curtis regarding what has been mentioned in this thread.
A little history re Panther. Led Cmek was a mechanic who worked for Denis in Vancouver, starting in 1972. In 77/78 Denis sold his business to Led, and he renamed it Panther. He was going to call it Greyhound, and use the Greyhound bus logo, but was informed of the possible legal issues, so used Panther. Led got from Denis all of his fixtures and jigs. Panther's primary business was flat track frames, based on Denis's improved version of the Champion frame. The only 750 frame Panther produced was a continuation of the mono shock frame Denis originally built for Robbie Mieklejohn. There are pictures of this very frame in my Speed Pony thread -
http://forums.sohc4.net/index.php?topic=74854.0. Denis is absolutely certain Led never built any twin shock frames for the 750. So the Curtis / Cmek / Panther connection to this frame, is very tenuous at best.
As for the Rob North connection. Denis knew Rob in England, and continued to contact him after Denis emigrated to Canada, and Rob North to the US. Denis stated that Rob North's only interest was in British engines, primarily the BSA triple. He also said that when Rob's company went under in England he, to put it politely, sought solice in the bottle. This continued after he emigrated, and he produced very few frames once there. Those that he did build, were also for the same engines. Denis is absolutely certain he never built any specifically for the 750. He also said that if the frame is a Rob North, then it is one of his BSA frames converted to take the 750.
Given all this, if the frame is a Rob North, and Panther was involved, then the best explanation is that it is a BSA triple frame that was converted by Panther for the 750.
On another note for KOS, and other CR750 interested parties. Denis told me that there is a real CR750 (not a kit bike) here in Canada. The bike's provenance is iron clad. I'm have the owners #, and if possible will try to go see it, and take pictures. When I don't know. However, if there is something in particular someone wants shots of, let me know. I'm also certain that KOS knows the bike I am speaking about.