Need advise on refinishing head and barrel fins

[copb8]

I'm starting to attend to some of the cosmetics on my 71 CB750. I started this last weekend to polish the cases and they're looking much better. But as with so many of these projects, once you get one thing looking good it makes everything around it look worse.

The fins are discolored and little corroded. I started using small circular brass brushes with my drill to clean it out. The brushes did a pretty good job of removing the 'patchiness' of the finish but they deteriorated very quickly and left the surface dull and almost dark colored.

Picture of fins before I started. Don't have an after picture yet though.

The brushes I used came in a variety pack from Northern Tool. I have no use for the plastic or steel brushes and really only need one or two diameters of the brass ones. Anyone know where you can find these in bulk in a single size?

Any other tips or techniques I should be using to make these fins look a bit better without removing or repainting them?

 

[MidlifeCrisis]

I did a job like that with a '86 Yamaha XJ700 a long time ago. Blasting with walnut shells did a fantastic job at removing just about anything off the surface, but did not "refinish" like it would be with anything more abrasive (sand, metallics, etc.) Glass beads are also a good choice and only a tiny bit more aggressive.