Keener,
I just finished my engine clean-up on a 1976 KZ900. Determined I was going to find a way to get them back without blasting and without clear coat. I was determined that I would have the shine finish or I would have to send these to England and let Stephen Smethurst do them for me. Mine were oxidized with white/gray scale, stained from years of neglect and oil leaks. I looked for something that would remove the scale.
I started by soaking them in $141 worth of NAPA's best 5 gallons of carb cleaner - nothing I soaked them in commercial, un-diluted aluminum cleaner acid would remove the scale - nothing but lots of foam and it turned the surface dark.
I soaked them in air conditioning coil cleaner - really strong stuff - same, still had the scale and the acid was turning it darker.
I used Purple Power, Greased Lightning - nothing would remove the stains and scale.
I called Stephen and during that conversation he mentioned that he has to put them into a "burnishing tumbler". This is not something you have at home. Unlike the vibrating polishers Eastwood (I have a small one), the burnisher is mechanically driven to rotate the part. I knew it was going to take something mechanical.
Determined that I was not going to blast them with beads, I looked for an assortment of wire brushes. I bought several different kinds and bristle type. I also bought several different round disc type to fit into my electric drill. In searching for one thin enough to fit into the fins and with long bristles, I found that the long, small diameter wire would easily go in between the fins and small areas of the cylinder, head, and cases. Once This cylinder was cleaned of grease, honed, gasket surfaces cleaned, then I spent 10 minutes with it on my bench, my son holding it for me and using an electric drill and that 5" fine-wire 1/4" think wire brush - I cleaned all of the scale and brought the original shine back to the finish. Use the right brush - not too still o it will gouge and you will simply be amazed at the speed and the nice shine that pops out. Every casting mark is left intact and the shine is probably better than new. Those wire disc are $4 each at many retailers like Lowes and Home Depot. I would imagine they are for paint removal. As a touch up, I would use a brass-bristle brush by hand to get any spots I'd missed. Those holes and small places? Wal-Mart sells universal gun-cleaning kits for about $10 which have 10 different steel brushes for small rifles and 12 gauge shotguns - those work perfectly chucked up into your drill.
Once you're done, wash the part in paint thinner or mineral spirits and then hot, soapy water, blow dry and lightly oil the bores and you're ready for assembly.
Hope this helps.
Regards,
Gordon
First pic - brush on left, beadblast right - no comparison.
