Project 42, a 1986 VFR750, is on the lift, and with the carbs and valves completed, I've begun work on the various rear chassis chores. Central to this work is the swingarm, which in this case is cosmetically damaged from some liquid etching the anodizing on the right side. I see this on about half of my projects, and I assume it's caused from vented battery acid which is blown back onto the swingarm by the wind.
This photo shows the result and it's only fixable by physically removing the anodizing then sanding and polishing the raw aluminum.
I cover this on my "Maintenance" page but here I'm doing only one side of the swingarm and doing it indoors. As always, I begin with a thorough degreasing and cleaning, taking care not to introduce any dirt into the needle bearings, which I will later wipe clean, inspect and re-grease prior to remounting the swingarm.
(Below) I strip the finish with spray-on oven cleaner — I need to contain the stripper so I spray some into a container and apply with an acid brush, wiping any drips or excess with a damp paper towel. After sitting for about 20 minutes I scrub with a non-scratch pad and wipe clean with a wet towel.
(click on an image to enlarge)
I cover this on my "Maintenance" page but here I'm doing only one side of the swingarm and doing it indoors. As always, I begin with a thorough degreasing and cleaning, taking care not to introduce any dirt into the needle bearings, which I will later wipe clean, inspect and re-grease prior to remounting the swingarm.
(Below) I strip the finish with spray-on oven cleaner — I need to contain the stripper so I spray some into a container and apply with an acid brush, wiping any drips or excess with a damp paper towel. After sitting for about 20 minutes I scrub with a non-scratch pad and wipe clean with a wet towel.
(click on an image to enlarge)
(Below) Here's what I'm left with. If you see any shiny areas of remaining anodizing, reapply the stripper till it's all removed. I then sand with 600- followed by 800-grit wet/dry sandpaper till I'm down to bare aluminum. The original corrosion left small etchings (pink arrow) in the aluminum, and depending upon the level of finish you're after these can be left in place or, as in this case, continue sanding to remove. I'll need to use coarser paper on these spots, but I've learned to never go below about 500-grit in order to avoid sanding marks which will be difficult to remove.
(Below) I want to match the other (original) side so my final sanding is lengthwise with the "grain" of the aluminum. In this case I found 800-grit to give a good match along with a single hand application of aluminum polish. When I'm happy with the finish I preserve it with two applications of Sharkhide. I can't forget the axle brackets — these appear to be stainless steel so I polish out any corrosion and discoloration with wet/dry sandpaper, then protect with Sharkhide, clear coat paint or a metal treatment. If you're OCD, like me, you can polish the flat screw heads by rubbing on sandpaper on a flat surface.
Ready for assembly!
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