Bike clean-up...any suggestions?

#1
Evening all,

To cut a long story short, bike’s been left outside for ages without any TLC. I know, I know. I’m now getting into the job of cleaning it up. The problem is this:

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It’s the wrong colour for rust, but it definitely feels pitted. Since the yoke has some kind of surface treatment I don’t just want to wade in with a wire brush.

Anyone got any idea what it is and how to get rid of it?
 
#2
It's the cast aluminium version of rust. Aluminium Oxide instead of Ferric Oxide. Possibly caused by dissimilar metals creating electrolytic corrosion when the bike and/or atmosphere is damp enough.

Full treatment would be to take it off the bike, completely rub it down till smooth and then re-coat it with a new finish.

Lesser renovation treatments are available.
 
#3
Looks typical of a component cast in alloy so it could figure non iron-oxidisation.
Chemicals won't do it. It looks too badly pitted to give you something you could live with.
It needs a new surface skimmed..a few microns hopefully.
The only way, in my opinion from working on old cars and alloys over many years, is to dismantle it and hand sand down to the bare alloy..or whatever metal is involved. I'd be wary of wire brushing too till you get the feel of it...alloy being softer. I can recommend both BiltHamber and POR15 products to finish & protect the new surface.

Hope this helps.
 
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#4
Ha. Given the reputation of Honda's steel components for corrosion resistance, I don't suppose I should be surprised to learn they've found a way to make aluminium rust :D

If surgery is the only solution, then surgery it is.

Bollocks.
 
#5
ACF 50.
Get it off ebay. I use it on my saltwater fishing kit, it'll eat that corrosive stuff right off and leave a protective film.

Mate who's a serious biker swears by the stuff.
 
#6
It's the cast aluminium version of rust. Aluminium Oxide instead of Ferric Oxide. Possibly caused by dissimilar metals creating electrolytic corrosion when the bike and/or atmosphere is damp enough.
Agreed, it looks like what you get if you stick a trangia in a dishwasher.

A brillo pad with a bit of water will probably get rid of it but will leave scratches in the surface.
 
#7
ACF 50.
Get it off ebay. I use it on my saltwater fishing kit, it'll eat that corrosive stuff right off and leave a protective film.

Mate who's a serious biker swears by the stuff.
Had I bothered my arrse to ACF-50 it before I went away, I'd probably not be having these dramas now.

Didn't realise it undid existing corrosion though. The yoke might be a bit far gone but it'll worth a go on the rear shocks.
 
#8
Ha. Given the reputation of Honda's steel components for corrosion resistance, I don't suppose I should be surprised to learn they've found a way to make aluminium rust :D

If surgery is the only solution, then surgery it is.

Bollocks.
Believe me Enkei alloys, fitted to generations of Mazda Mx5s, Hondas etc have been the utter bane of owners' lives for nigh on 30 years and often triggered warranty "no quibble" replacements. Alloy "osmosis" is pretty common in over-porous Roadster cylinder heads as well as numerous other components. I'm on my third in 14 years.
 
#9
As above, ally corrosion. Depending on how good a finish you want, use wet n dry to remove the loose oxide then paint (1st step to ratting it (dead cheap)), to paying someone else to collect, disassemble, send off to polish the corrosion out, then get it hard anodised and reassembled before returning it (How ******* much????).

Cheapish option is remove it yourself, and polish with a drill polishing head. Start with a softer head than you think you'll need. Probably much softer. It's easier to re-try using a harder head to do the job than it is polishing out the damage caused by starting out with an overly abrasive head. Yes that is the voice of experience. Then either paint / lacquer it yourself, or, for a (much) better result, have a local company do it. How much they charge will depend on how much of the grubby prep you do.
 
#10
Strip it down, flat off all affected parts and re spray with aerosols , fork legs look fcuked so order new stanchions and seals , if you want to have a high end all weather resistant coating look at cerokote.
 
#11
Everything the above have said but just to add - you're worrying about nothing.
I'd give it a rub over with wirevwool and an oily rag if I didn't want to disassemble anything. Sand it and respray if disassembled. Consider having it polished depending on whether I wanted to customise or restore.

Whenever you're doing maintenance on any alloy like this it's a good idea to wipe the oxidisation off, spray with WD40 or wipe with oily rag but most importantly...
Grease or Copaslip any steel fasteners before they start an electrolytic bond. They can look sound but crumble the entire thread if left neglected.
 
#13
Google "filiform corrosion" - I don't think I can give a concise description. It tends to start at pinholes in the coating, either a coating fault or a tiny chip. Perversely, it doesn't seem to propagate as quickly if there's a large area of coating damage.

It doesn't tend to penetrate very deep (at least, not for a long while), just on the surface of the alloy. It spreads fairly quickly though but doesn't expand quickly like rust. A result of this is that you'll see very fine threads that don't appear too major yet soon afterwards a big area of the coating will fall off.

Lots of theories as to why it happens - because it doesn't always happen. There's more to it than just exposing the alloy to air, and it certainly propagates without exposure to outside air. Oil, perhaps from skin touch, prior to coating might trap just the right amount of oxygen to get the process started but, last I heard, this was only surmise.

Fixing it isn't easy. When we found it on powder-coated aluminium cladding, none of the techniques we tried was effective (new filiforms started at the edge of the repair, regardless of how far away we feathered back), so replacement was generally the way forward. Stripping the coating from the entire component and fully encapsulating might work but that's something that wasn't practical on a cladding component.
 
#14
To be honest if your taking it off you may as well buy a secondhand be in good condition and swap it out then stick the other on eBay and get some cash back. Somebody will have smashed up his bike and want a functional one.
 
#15
To be honest if your taking it off you may as well buy a secondhand be in good condition and swap it out then stick the other on eBay and get some cash back. Somebody will have smashed up his bike and want a functional one.
To be fair I've been looking at prices for other parts, and it's so cheap I'm tempted to just repair by replacement. If I have to strip all the switchgear off anyway...:D
 
#19
Insure it fully comp,

Buy an Thatchen approved lock, keep the receipt.

Park it up unlocked of course,

It will be borrowed permanently by the scallies.

Report stolen to the Police, obtain Crime No,

Ring Insurance company,

Await cheque,

Buy new motorbike,

Job jobbed.

If found out and banged up for a few years, rusty motorbike parts will be least of your worries!!!!!

Disclaimer the above advice is tongue in cheek and I am not aiding and abetting nor sharing a prison cell with you.
 

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