Alloy polishing

[MrDavo]

While I like the vapour blasted finish on my CB750 engine, it isn't appropriate for either the fork lowers or the engine covers, but that's how I got it. The cam cover can stay how it is for now, as I can't be arsed to take the engine out just to polish it properly.

Although it is something I could possibly have a go at myself in the winter, anyone know of a decent polisher in the North West, and have an idea of the cost?

Anyone had a go themselves? I reckon the first 'cut' will have to be quite aggressive to remove the matt finish I have at the moment. Also as I want to laquer the result, both so it looks original, and so the 'monkey metal' alloy doesn't go nasty too quickly. How do you finish the alloy to key the laquer, and what laquer did you use?

Any tips or experience will be gratefully received.

[AshimotoK0]

Welcome,

See here, Pretty sure original K1 finishes as K0

http://www.sohc.co.uk/index.php/topic,8887.msg60610.html#msg60610

There is some stuff called Alodine used to prep alloy but expensive and nasty stuff. Some people have suggested powder clear coating but not tried it,
I am sure with various grades of wet and dry and Solvol you could polish, or geta sizal mop and polishing 'soaps kit. Problem is getting the correct original satinised finish on fork legs. Going to try all this myself over the next month so I will let you know.

Ash

[Orcade-Ian]

Hi folks,
Getting that finish back on the forks is usually only an hour of a job.  Things like cam covers with awkward corners are a bit more of a challenge.
Some time back I put a little 'how to' piece on my web site about this very thing. I'm away in Germany at the moment, so I don't have the link to hand but if you go to my site (the globe near the avatar)and have a look around the GB 400 TT section, I think it's there.
Hope this helps,
Ian

[Orcade-Ian]

Ah! Just found the piece in GB 400TT part 2,
Ian

[Bodd]

There is a bit on my web log of how I polished the forks on my cafe project, near the bottom of this page, after I rebuilt them I buffed with a lambswool polishing mop as can be seen on this page 8th picture down. I didn't lacquer them though, I just give them a light buff by hand from time to time with Autosol then polish with AutoGlym Super Resin for protection.

[MrDavo]

Thanks for your tips ans links, over the winter I will take the fork lowers off (and fit Progressive springs at the same time) to polish them myself, and also the alternator and gearbox covers too as time allows. Sod paying someone else to do a job I could do myself over long winter evenings.

I have a good rotary polishing mop / grindstone as well, unfortunately I no longer have a workbench to bolt it to.

[MrDavo]

Just a quick update, I managed to acquire an old cast iron machine stand from one of my clients, in exchange for doing a job for them. Ive fitted my vice and polishing / grinding wheels to it, it's just the job for the limited space left in the garage after a car and 2 bikes.

At weekend I took the forks off, a lot of nasty goop came out from under under the fork gaiters, which were soft and distorted by the oil, so I got new Honda seals and gaiters from David Silver. Absolutely no trouble changing the seals with the forks off the bike, once I'd bought a suitable pair of circlip pliers from Halfrauds. I used the old seals to push the new ones down below the circlip groove.

 I removed and refitted the fork caps outside, as I was worried about one either going through the concrete garage roof, or bouncing around until it found the 911, but no problems at all - distressed forum posts made me expect it to be a much worse job fighting against the spring pressure. I also used 210ml of 10/30 grade oil as recommended in my Honda manual, downloaded from Ash's link on here. I want to try the original setup first, before I play with different springs or grades of fluid.

Anyhow, I polished both fork legs no problem. Ive had to leave them shiny, attempts to replicate the 'brushed' finish using wet and dry just didn't look good, the hard part is getting an even finish that looks like it was done with a machine, I tried but ended up repolishing the fork lowers. A bit torn between whether to try  laquering or not, a mate with a classic bike shop says I'll only end up taking the forks off to repolish once the laquer gets fogged, chipped or crazed. The bike isn't going to ever see road salt anyway, I hope.

The forks aren't back on yet, but look infinitely better than the dull vapour blasted finish they had before. Using the rotary polishing wheel and a bar of polish I bought years ago, the job was far easier than I expected.

Cosmetically, the shiny lowers, new gaiters and swapping the large (K2 and later) reflectors for the new correct small K0/K1 ones should make a huge difference, I'll take a picture when it's done.

[Pops400]

Some great info on those pages. 

Doing my research. I have a lot of this to do. 

[MarkCR750]

I use autosol instead of the polishing wax, put it on the component not the mop, great finish an no annoying wax smears to get rid of.

[PHILIP2908]

Hello Gents,
Re alloy polishing: the DK special is fast turning into a DS special and needs far more work than originally envisaged.
I failed to spot the worst head gasket leak ever and so the engine is out of the frame. Whilst out, I took the only opportunity I would have to polish up the scabby valve cover. Hopefully the attached image is there:
Cost £50 and trouble is that I'm going to have to get the rest of the engine up to the same standard....
Done by I&P Polishing just off junction 9 on the M5 at Tewksbury tel 01684 274094. A one man band who normally does aircraft under-carriage legs but takes on little jobs like this too.