I have some manuals in digital form on the 1200 Harley U...and other models covered in the same manual. Mail me if you're interested.
The Jan Willem Boon 2006 catalogue for '36-'47 Knuckles af 1200/1300 Flatheads from '37-'48
1940-1947 SERVICE MANUAL for Harley Davidson KNUCKLEHEAD & FLATHEAD.
Old Dirty Motorcycles