Nice find. Quite a late one too.
Is it like this model ?
http://www.veteran-motorcycle.com/raleighMH31.htm(click for bigger pics)
Raleighs are quite well thought of in the vintage world, and were quite popular, also selling engines and gearboxes as the Sturmey Archer brand, so there should not be too much trouble finding parts lists and brochure pics for it.
The Vintage Club in the UK - VMCC - would likely have these - and should have a marque specialist, who can advise on most of the difficult questions. Later Raleigh ohv bikes were reportedly designed by someone who had worked at Nortons, and there is a similarity between the 2 makes - Sturmey supplied the gearboxes to Nortons also,
Raleigh Industries still exist, as bicycle makers (?) and are proud of their manufacturing past and have a website with some history and pics. They ceased making motorcycles in the early 1930s, and your bike must be about then too.
http://www.raleigh.co.uk/Company/History/First step in the restoration process is to take good close up shots of everything, like you have been doing,
so you can see exactly how everything fits together and what goes where.
The next step is making a rough list of everything that seems to be missing - and checking if the recent owner still has any of these parts nearby, or stored on shelves or in boxes etc. Or if he knows where they are. Finding the original parts is much better than trying to obtain them off ebay etc - or having them made. Making contact with other Raleigh Owners will probably open up a whole world of information and spares sources and providers of services, Most owners will welcome contact with another owner of a similar bike, and share info etc.
Whole books have been written on how to restore motorcycles, so I won't even attempt that here !, but its largely a matter of photographing everything FIRST, taking everything to pieces (maybe one piece at a time), cleaning or painting or chroming it, making all the mechanical parts new or good enough to use, and then assembling it back into a motorcycle again.
Document everything - always good if a record is kept of what has been done, and useful if anything needs to be redone etc.
We will look forward to progress reports and pics, and any questions etc.
Have fun.
