Found a Japanese Motorcyclist magazine, May 1969, on eBay.
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F264365610598
The seller posted pictures of an article on the XS1 Proto, possibly spy pics.
Snagged some copies from the listing.
Cleaned-up, resized...