Steve O you think that its better to leave unpainted (clear) even tho that's how they have them from the factory? Why do you prefer not to paint?
I've seen pics of the clear coat yellowing over bare aluminum, and I would not want to risk that.
My bikes stay in the garage every night, so there is really no need to coat them for the elements. If your situation is different [?], then coating may be a better option for you.
+1 on not clear coating your finished aluminum pieces. Like i said, i've never restored a bike but have worked on aluminum pieces. It's easier to keep these pieces looking good just by polishing them every now and then.
Honda's original clear for the aluminum parts , was likely a good ,strong lacquer. That was the primary type of paint being used. I've tried various " clears" today , and not the inexpensive stuff ( i use eastwood products a lot) and i feel they do tend to yellow...and " spider" .My eastwood clear did that. So, it would suck to finish your parts and have that happen.
one final note, i'd take a scrap piece of metal and spray it with whatever primer you may use ,if you decide to, ..and then spray your black paint just to make sure they are compatible. It would also suck if you primed the frame, then began spraying the black and watching it wrinkle up....just fyi..