Hey Ross, What do you mean all Montys stopped after 1982?
That snow equiped 349 would be an interesting bike/thing. I have one of those bikes and the frame and swingarm are not exactly over engineered. After all it is a trials bike built to be as light as possible. I think flex would be more than a minor issue unless the frame and swingarm have been totally re-engineered. The sump guard forms the lower part of the frame and the swingarm is lighter than most pre LTR 125 MX's.