Robinson’s foundry ended up stocking the oil level glass thingy. I just placed an order with them and everything should be shipped next week or so. 
Another productive day and lessons learned. I finally got the bearing race off the stem, thanks to Miltons advice on gsx1400.org. The stem did take a bit of a beating in the process.
I also had a go at brushing out some aluminium bits. I guess they still need to be polished to make them nice and shiny instead of the irregular brushed look.
 
I also got around to taking the brake calipers apart. I borrowed a diving tank from a friend and popped the pistons out. Pretty grimy. I’ll be soaking them in brake fluid, once I remember to pick some up. I had a very humbling learning experience while fiddling about with the calipers. I was certain that the outside piston were truly madly stuck and wouldn’t move no matter how much pressure I put in. Turns out it’s a good idea to bolt the brake line connection to avoid all the compressed air escaping. I felt pretty stupid, but got all the pistons out in the end.
I got around to cleaning up my swing arm good and proper as it will be sprayed next week too. I’m still toying with the idea of replacing the swing arm bearings, but is there any sense in that? I can’t imagine they they get worn out too much?