Hi ,
I am just rebuilding my old (87) KRT and would like to polish up the engine cases. I have the impression that BMW chooses the finish on these castings especially to stop nerds like me shining them up. Othere than elbow grease has anyone found any shortcuts ?

Soda blasting can work. Don't sandblast as likely you won't like the results (tried both). 

There's a host of foaming/soaking etc. aluminum cleaners on the market, but use a 'test' spot before going all out as the finished result can be uneven. Stay away from muriatic acid (don't ask).

You can use a wire brush/drill combo but make the brush brass and exercise patience and caution as once you start it you're committed, so to speak. 

Get a bottle of Marvel Mystery Oil if avail. in your area and a Scotch pad and be amazed at the effectiveness of the two combined (+ elbow grease).

I've seen some good results with Hydro blasting, but you will need the covers off to give them to the man with the big hose. Then either clear coat or steel wool rubbing once a year. Or be like me and paint them black again
and have it peel off after a year.
RT

Nowhere man wrote:Hi ,
I am just rebuilding my old (87) KRT and would like to polish up the engine cases. I have the impression that BMW chooses the finish on these castings especially to stop nerds like me shining them up. Othere than elbow grease has anyone found any shortcuts ?

Hi. I have done extensive polishing on a lot of engine casings over the years so I may be able to shed a little light on your query

First, it depends on what level of finish you are looking for and what level of stripdown you are prepared to undertake. If the parts are painted and you are just cleaning then cutting compound like the panelbeaters use, and a soft cotton buff is usual

If it is just a clean bare aluminum look then you can go for the wire brush on the end of the drill. There is a very thorough thread here somewhere doing just that.

If you want to do all of them to a really high standard of clean (bell housing included) then I would suggest taking the cases to an engine rebuilding shop that has a paragon tank. Paragon is a very effective cleaner. You soak the cases and pretty much just brush off the paint, leaving lovely shiny raw new looking aluminum. Of course the cases will discolor over time (go duller) but for about $80.00 it is pretty effective way of doing the job.

If you are after a higher level of beauty you can of course PAY THROUGH THE NOSE to get them polished by an electro-plating / polishing shop. Mine cost me neary $600.00 NZD for just the crank, valve and timing chain covers but they came up mint. Then there was the other $300 to get them done in diamondshine 1300 degree stonechip proof clear coat. The beauty here is I NEVER have to polish them again and they always look great and just get cleaned along with all the other paint

Or . . . you can do as I did with my gearbox, block, bell housing and footrest plates and front forks and brake callipers. I sand blasted them and painted them in VHT aluminum coloured paint, followed by a VHT satin clear coat spray can

But the paints do not have to be VHT. We have plenty of reports on this forum of members achieving pretty good results using just ordinary paints.

I am a fastidious bastard when it comes to restoration and surfacing so I went the whole hog on mine but, unless you have pretty deep pockets and are a real big fan of bling, and love dis-assembly and reassembly most people won't go to the efforts I did as they fail to justify the expense and time involved

If you do get them polished and do NOT seal them then you will be forever polishing your bike and not riding it much to keep it looking nice

hope that helps

I get mine done in "Chromex" ceramic coating for $60/side engine cover which includes media blasting to clean them up prior to coating. (No tax if I pay in cash as it saves them CC fees and improves their cash flow.)

duck wrote:I get mine done in "Chromex" ceramic coating . . .

Nice. Looks really clean!

Just one question . . . how do you ride 8 bikes at once . . .;-))

He reckons he is going to sell 4 of them. I've been waiting for ages to find out which 4  

One of the worst cases of Kpox I have ever come across.
Next thing is he will make a shrine to them ...........er well come to think of it........http://classickbikes.com/ckb.tech/ckb.tech.toc.htm he he he

Check out the post by Motocol on his making of a K100/2

About as shiny as you can get

Motocol

I'm in the process of doing this atm.

1. It's really important to get the alloy really clean first. For that I've used Chemtech Blitz Aluminium Cleaner (1 lit about $20). It's 382g/l phosphoric acid (Rust Converter I think??). I use an old paint brush and treated my casings twice. They came up a treat, removing stubborn dirt and stains and removed all oxidisation. It also get right into the grainy texture of the covers and cleans them righ up.
WARNING: Do not get this product on any plastics (and there's a lot of black plastic around the engine. It will bleach the colour right out and the longer you leave it the deeper it goes. Wash off immediately. You might be able to polish it of. This happened to my oil filler cap. Regarding use on other metals such as stainless and chrome... READ THE INSTRUCTION FIRST. Stainless steel will go matt finish but it polishes back up very easily.
You can dilute it if you want but I used it straight out of the bottle.

2. Finding a polish that will bring it to a bright lustre is dificult and I've tried quite a few. None really work all that well. My daughter put me onto Californian Custom. She's just done her SR400 cylinder fins and from the photos they've come up very shiny. And if a girl can do it... say no more. She said it was pretty easy but she did also use the CC deoxidiser which may figure into the process. Don't know what's in the CC Deoxidiser. Have just ordered the CC Purple Metal Polish so I'll let you know how that turns out but from all reports from other sources its the gear to use.
http://www.californiacustom.com.au/california-custom-catalogue

3. As far as sealing the surface so it doesn't re-oxidise... I'm just experimenting atm. However, I've been using a product from Turtle wax called Black Wax on all my plastic. It works really well. Read my post on that here
It's a watery solution containing carnauba wax with a black dye. I've applied this the the crank case cover only and it has given it a nice patina sheen which I really like. Its been a few weeks now and that cover still has a nice sparkle to it where has the camshaft cover has gone dull again. I'm not really into paint or chrome or getting away from the original look.

As I said Ive just been experimenting but if it's a high shine you want, the Purple Polish from CC looks promising. You might be able to buy at your local auto store but I've found it to be twice the $ as online.

Cheers

Kaptain Holister wrote:3. As far as sealing the surface so it doesn't re-oxidise...

This is what I used. Absolute magic

http://www.kbs-coatings.com.au/product/diamond-finish-clearcoat/

Features

• Over 60% solids in single pack
  
• Tougher & harder than 2 pack clears!
  
• Seals both paints & metals
  
• Self levelling (no brush marks)
  
• Brush or spray application
  
• Hi Temp resistance
  
• Permanent UV stability
  
• High chemical resistance (including fuels & solvents)
  
• Graffiti proof
  
• Recoat in 1 – 2 hours
  
• Seals ferrous & non-ferrous metals
  
• Developed, made & tested in Australia
  
• Gloss finish for lasting shine
  

RicK G wrote: . . One of the worst cases of Kpox I have ever come across. . .

Hmm . . I must have had an extremely lucky escape.

After buying one, and then another one I have managed to reduce myself down to only one again and a handful of spare parts.

Be made wrote:

Kaptain Holister wrote:3. As far as sealing the surface so it doesn't re-oxidise...

This is what I used. Absolute magic

http://www.kbs-coatings.com.au/product/diamond-finish-clearcoat/

Looks like an amazing coating but I'd like to see what it looks like in a few years and how it has taken the weather.

I'd like to stick to the au naturalé look

Kaptain Holister wrote:

Be made wrote:

Kaptain Holister wrote:3. As far as sealing the surface so it doesn't re-oxidise...

This is what I used. Absolute magic

http://www.kbs-coatings.com.au/product/diamond-finish-clearcoat/

Looks like an amazing coating but I'd like to see what it looks like in a few years and how it has taken the weather.

I'd like to stick to the au naturalé look

Well. Dec 2012 to now, so far 10000ks and no change. The finish on the cases is still looking like the day it was done.:

Hope this helps.

Lets see what another 20 months brings

At Build:



Today:

Yup. Can see that that has held up very nicely.

Notice you've changed your bars as well. What are they?

Kaptain Holister wrote:Notice you've changed your bars as well. What are they?

Aftermarket somethings. . . $65.00. I wanted others but would have had to extend everything

this is my thread:

https://www.k100-forum.com/t5107-89-k100lt-k100-custom-conversion

and the post about the bars:

https://www.k100-forum.com/t5107-89-k100lt-k100-custom-conversion#58729

the best part was the 500km round trip I did on the bike to pick them up . My partner was great. She pillioned and carried them all the way back from New Plymouth :-))

It was an awesome ride through the beautiful Awakino gorge and up over Mount Messenger

The only way I know to polish these alloy castings is with elbow grease, that means start with 240 grade wet & dry then about 400 and finish with 1200 grit, then use some cutting compound and the buff.
This swing arm took about 2 hours from cleaning to buffing and is by no means show quality, the more elbow grease put in the better the finish, I'm just cleaning this up for clearcoating. 
Before cleaning.


After sanding



Then a buff
 



 

smithy wrote:The only way I know to polish these alloy castings is with elbow grease, that means start with 240 grade wet & dry then about 400 and finish with 1200 grit, then use some cutting compound and the buff.

Yep. that's the one. I did quite a few bikes years ago like that. I used an orbital finishing sander, those grades sandpapers and the cotton wheel on the end of the drill. These days money replaces labor so the shop ended up doing mine this time