Engine Polishing

Hello, since a few month i ve got my second commando. The bike is fine but i want to polish the engine block. what is the best way to do it, that it looks very nice? Thanks for your help..and sorry for my language....kurt

Hello Kurt, welcome to the world of Commando. I find the best way to clean the engine, starting with the rough castings - crankcase, inner gear case and cylinder head is use a strong degreasing fluid with a paint brush that you cut down the bristles to maybe 2cm so that they are stiff and can penetrate the rough surface.

To clean and polish up the head fins, I find the best product is what we call a "Scotchbrite" pad, this is a green tough nylon pad used for scrubbing kitchen pots. Fold this into the fins and push and pull it through the fins. It also works well on the crankcases. When you have done several hours of this (beer helps) then you can start the actual polishing.

For the shiny bits like rocker covers, if they are dull, use wet & dry emery paper, start with 600 grade and finish with 1200. Use a polishing paste with the 1200 and then repeat with cotton rags.

I use Sovol Autosol, also Mothers alloy polish is good. I use a rough cotton rag to rub in the polish paste and then buff it with a clean cotton cloth.

Mick

I am polishing stuff on my project and what I found works best is to first use a power sander (I use an orbital sander with 220 grit discs) to make the surface as smooth as possible, then I use a cloth disk mounted on an old electric motor and I dab it with jeweler's rouge and then it takes time, and more time.

I built a small box around my wheel and I have a dust extractor to keep the dust and grime in check otherwise, do it outside and pick a windy day.

Here are my lower fork legs after sanding and polishing. You will notice I removed the tabs holding the mudguard stays, so I had to sand and polish to make them look like that.

Jean

Jeandr I am impressed with your polishing . I would have thought 220 to be too coarse prior to buffing with rough. Must work. I usually just buff with rough unless there are severe scratches.

For polishing, I use 320 on an orbital sander to get the large scratches out. Then I hand sand with wet N dry 600. Then I buff with black compound and a sisal wheel. That seems to get it down good enough to buff with another buffing wheel and red rouge. I use an old furnace motor, but it would be better if I had a bit more power. Make sure you clean the parts between using the different compounds and use separate wheels for each compound. If you do a good job with the 600, you can probably skip the black compound. You have to make sure you get the larger scratches out with each succeeding paper, or you will never get a good polish.

A steel brush or the scotchbrite stuff works good on the rough surfaces.

Dave
69S

Hello commando friends, thans a lot for all the good tipps and tricks. so i will go ahead with polish up my bike and hope it will work. best regards from switzerland, kurt

Picture of my setup. Aluminum is pretty soft and only using the polishing wheel after sanding the big scratches seem to to do it for me. I wear gloves, heavy gloves, when polishing, for protection of course, but also because the parts do get hot enough that I can't hold them anymore.

Jean




And more polished bits...

I'm not an expert buffer but recently did a ton of web research. For aluminum it is recommended to start with Black emery compound, then Brown tripoli and finish with White Rouge. If you use the popular Red Rouge (Jeweler's Rouge) it will immediately give your aluminum dark undertones. Using the 3 compounds listed above maintains a whiter look to the aluminum.

You can download caswell's guide for free here:

http://www.caswellcanada.ca/shop/downloads-amp-links.html

Wax?

While I am satisfied with my polishing method, I have a question on keeping it nice for a long time. Is it a good idea to wax polished aluminum?

Jean

Re: Wax?

Jeandr said:

While I am satisfied with my polishing method, I have a question on keeping it nice for a long time. Is it a good idea to wax polished aluminum?

Jean

Click to expand...

You have a nice set-up there. I'm going to have to wrestle my buffer outside every time i want to use it.

I tried to find the info I read earlier online about polishing. While most people advocated using a final finish like mothers or solvol the old time pros always chimed in saying not to do a finish sealer and just leave it. The pros always indicated regular maintenance was necessary and after the 1st initial job it was easy to keep it shiny. (maybe they've never worked around spokes) After a lot of web crawling i was left with the impression that #1- Black emery compound/sisal wheel followed by #2- brown tripoli/stitched wheel and finally #3- white rouge with a soft cotton wheel was the final finish. Anything else goes into the surface and changes the look.

To practice I did my end cones on my bench grinder (that hold the main bearings on the shaft at the ends). They were never made to be polished and were rough cast and rough turned then painted. I used a wire wheel to take the paint of then 80 grid sandpaper and gradually worked up to 600 grit emery all hand sanded. At that point they looked awesome. I read how using red rouge on aluminum would make it go dark but after combing the city all I could find locally was red rouge and since this was a learning project and i'm so impatient I used the red rouge on a stitched wheel. Immediately I saw the aluminum go from a light color to a dark tone and understood what the pros were saying. Since I started on only one end cone I still had the other one to do after my buffing kit arrived from caswell. That side I did without the red rouge so now one side is a little darker than the other. The other thing the pros seemed to agree on is sanding with anything finer than 400 or 600 is a waste of time as the abrasive compounds will take over from there and you can use your electric buffer.

This is one of the sites:

http://www.finishing.com/

Can you post a picture of the two pieces side by side? Do you feel there is enough of a difference for me to throw away a big stick of rouge?

Jean

I have a bad cold right now so i'm not going out there to take photos. I think the pros become purists and see finer details than most lay people. Even though i saw the aluminum go from silvery white to a kind of bluey dark tone it still looks good. It may depend on your tank and frame colour just what you like. Rules are made to be broken.

I got 6 huge bars of compound with my kit as it was a good deal and I figured it made sense to get a kit in the beginning and add the little bits as I discovered a need for them (so i wouldn't through away the red rouge, it's good for most other metals). Your fork legs look great and I'd be happy with them.

Re: Wax?

Jeandr said:

While I am satisfied with my polishing method, I have a question on keeping it nice for a long time. Is it a good idea to wax polished aluminum?

Jean

Click to expand...

The rice boyz rave about a product called Zoop Seal for sealing polished alloy wheels. The manufacturer claims it keeps aluminum from oxidizing for 2-3 years. Summit Racing carries it.

Be aware that it's expensive and has a limited shelf life. If you don't use it right away it will harden in the bottle.

2-3 years... Kind of reminds me of the clear lacquer they used to (still ??) put on japanese aluminum parts, after a few years, it would yellow, then crack, then corrosion would get behind the coating then it would start to look like s#!t I think I will just leave it naked and clean it up with polish once in a while.

Jean

Jean, that is a cool polishing setup.

....and great work, by the way.

I have my polishing done by a small production shop that does work that has made the Honda Museum.
They reccomend leaving it bare and hitting it with Semichrome now and again because any sealers tend to put off corrosion for a while and later cause it.