These are stainless bolts. I have turned the heads to remove any markings. You can do this with a file or even with a belt sander but I like the look of them turned on a lathe. If the heads were taller, they would look even better. The washers are aircraft washers - thicker than usual. I got them from Airparts Inc. here in Kansas City. I would think most major cities would have an aircraft building place. It's worth looking a place like this up. They have tooling received from the aircraft industry. The tooling is mostly used but they are retired far before their useful life is up and they are quite inexpensive. USA-made end mills are like $3-$5, reamers $2-4, etc. It's at least 1/4 the price of new USA tooling. They also have fasteners, AN fittings(new for a couple bucks each), safety wire, Chromo tubing, 6160 plate, and basically most things you need for aircraft maintenance. My grandfather used to say, "If you can't find it at Ace Hardware, then you don't need it." I'll admit, Ace/True Value has more random stuff than large home improvement centers but they are expensive and I'd rather get bulk aircraft quality stuff. 25 new washers of about any SAE size are about $2 so I just grab a few baggies everytime I go. I need to make a list so I get stuff I don't already have. Man, am I rambling or what?
Oh, I found this choke cable there for $1. It will be a good period-looking sleeve where the throttle cable exits the handlebars. I would think that you could strip some bicycle brake cable housing and use that too.
Okay, here's the plate I made to cover the oil filter mount. There is a channel milled in the back that allow the oil to bypass from the filter feed to the return. I mentioned it before but you can see how ugly the filter would be by looking at the older motor posts.
It really stuck out there, wasn't needed, and didn't look the part.