I'm now well into dismantling my 1985 K100RT for a refurb and ready to start cleaning up the engine casing of oxides and road crud. Question: do I restore the engine to its former polished glory or do I have the engine covers powder coated to save on future elbow grease. 
Any comments?

Hi Aladin1

This is my opinion and I am in no way suggesting this is the only approach to cleaning the engine.
Many riders take the approach of sodablasting and painting the engine cases.
I have noticed those who adopt this approach often find the cases oxidize within months of been cleaned. Sodablasting/sandblasting seems to damage the cases and then you are left with a situation where the cases have to be painted. 
Painting the cases might seem like a permanent solution but it's very easy for the surfaces to be damaged by stones and road debris which then allows moisture to penetrate the paint layers and create bubbles beneath the paint surface.

Bmw never painted the engine and gearbox. But it seems a protective coating might have been applied which might explain why the cases don't oxidise. Sandblasting perhaps destroys the original finish and they begin to oxidise which gives a horrible appearance.
Halo and other riders have mentioned this situation.
My approach was to use an abrasive nylon brush attached to a drill and use a lubricant such as WD40. My cases look great and after twelve months there is no sign of oxidisation. 
Steel brushes are a big no no. They damage and remove the original surface finish and starts the oxiddisation process.
It's also a much cheaper option.
That's my opinion.
Feedback is appreciated.

Good luck with your Reno.

Cheers
Gabriel

Hi Gabriel

Thanks for your valued comments which Have definitely swayed me towards polishing the engine. I was going to try nylon abrasive pads with an aluminium cleaner but I'll try the WD40 method first.
If my engine stays as oxide free as you suggest it might I'll be very happy as I am an unashamed fair weather biker who rides purely for fun and avoids our UK winter salted roads like the plague. 

Regards, Aladin1.   

Vapour blasting will work well. It's a two-stage process; first the crud is cleaned off the surface using a very fine slurry and then the surface is effectively re-sealed when it's actually vapour blasted. I have a Moto Guzzi LeMans IV engine that was vapour blasted over four years ago and it still looks brand new.

Hi Dai

I've just had a look at vapour blasting on YouTube and it looks very effective. I don't want to strip the engine any more than I have to as it is mechanically sound but the engine covers could be blasted if the surfaces are resealed during the process. Was your Guzzi engine a Matt finish after blasting or does the process leave the surface clean but smooth?

Regards Aladin1

gabriel wrote:Steel brushes are a big no no. They damage and remove the original surface finish and starts the oxiddisation process.
It's also a much cheaper option.
That's my opinion.
Feedback is appreciated.

Good luck with your Reno.

Cheers
Gabriel

First, I don't think the aluminum engine parts have a surface finish on it. Just look at old rice cookers and you will see that with age the varnish starts to peel and become yellow.
Even if the BMW had a coating, the oxidation would be the result of the protection being destroyed. Using a steel brush would remove it totally to have a uniform surface.
The only bad think about using a steel brush is that it could leave particles of metal which would be embedded in the aluminum resulting of tiny little spots of rust. (I never had that happening to me)
What ever you do (at the exception of painting) will always be a temporary solution and corrosion will always re-appears.
I polished my engines with a steel brush and finished it with a nylon pad.
Every year, I just have to spend a couple of hours to refinish the engine with a nylon pad.
To clean the engine(and the painted surfaces too), I import a product from France called abnet
It is incredible but not imported in North America. If you buy some, DO NOT show it to your wife. She will love it and you won't see the container again. -
Do not buy the ready mix one as it has 90% water and 10 % product. - Buy the concentrate and dilute it yourself
This product has the property of going between the support and the dirt (even greasy dirt) and lift the dirt off.
You spray it, let it work for 1 minute and then rinse it. It even work with oxidation.
Imagine, when I go on vacation to France, I prefer to bring back this product in stead of duty free French wine.....
I never found anything better, and it doesn't contain any chemical components. It's even safe to clean your dish with it. The only thing is that the smell is not the most pleasant but it dissipate within minutes.


Look how clean these engines are.... Not shiny like chrome, but just clean and free of oxidation

indian036 wrote:"To clean the engine(and the painted surfaces too), I import a product from France called abnet"


You could have mentioned this before I left France two weeks ago.       Now I'll have to wait till September or so.


Bill

Or you could bribe TacKler to bring some back in June......

Hi everyone

I a happy to post photos if somebody can explain how I can post photos using an iPad.

Cheers

I agree with Crazy Frog. 
I used an abrasive nylon brush attached to a hand drill at a high speed setting and a lubricant WD40. A nylon wheel was difficult to use on the engine and gearbox, final drive and swing arm.
This method will give you a nice çlean finish. 
Be careful you don't use excessive force or you might develop swirl marks on the cases. 
You are more likely to scratch the surface using steel brushes.
I don't think polishing the cases is realistic.
Vapour blasting is an option but you have to completely dismantle components. Lets not forget the cost.
Good luck.
I would live to post photos but don't know how.

G'day All , there was a whole thread about using "sunlight" soap & steel wool , I use "velvet" soap & steel wool ( on the cases ) & they look great

John R

Melbourne Australia

aladin1 wrote:Hi Dai

I've just had a look at vapour blasting on YouTube and it looks very effective. I don't want to strip the engine any more than I have to as it is mechanically sound but the engine covers could be blasted if the surfaces are resealed during the process. Was your Guzzi engine a Matt finish after blasting or does the process leave the surface clean but smooth?

Regards Aladin1

It's more of a satin finish rather than anything else.

Gabriel, can you describe the nylon brush used in a hand drill in a bit more detail?
Is it something you would buy in a hardware shop or tool store?
By the way, I can't upload pics from my iPad either.

Comberjohn wrote:.....
By the way, I can't upload pics from my iPad either.

Nor from an Android device

Hardware stores usually stock these brushes.
Try and find an abrasive brush which will do the least damage to your cases..I prefer nylon brushes which are easier to handle and manoeuvre around the cases.
Josco is an Australian company which manufactures nylon brushes.
You will most likely have an equivalent product in your country.you don't need an expensive hand drill, but it's important that you select a high speed.
Try different speeds and you will notice when the nylon brush starts to clean your cases.
My engine was not corroded. Not certain how deteriated your cases are but I suggest you have a go.

This  type of brush  Gabriel?

Hi Dai

Satin finish is good for me. I think I'll have my covers vapour blasted and try the WD 40/nylon brush method on the engine block. 

Regards, Aladin1

The image didn't download
Go to bunnings.com.au and do a search using the keyword "nylon brush".

Thanks gabriel. Nice tip. Cheers

Technical info including grit and rpm from here
http://www.josco.com.au/newsite/jia/products/brushware/josco/josco_an.htm

And this is interesting...
http://www.josco.com.au/newsite/jsf/brush_products/abrasive_nylon_brushes.htm

Check out Alexander McCarthy and his water (hydro) blasting

HYDRO

And his thread on his TIC resto

Also look at almost any thread started by MIKE P

Hydroblasting us an option, so is gold plating....the issue is how much do you want to spend?
I believe BMW didn't paint the drivetrain including the engine for a reason.
I have seen many paintjobs ending up looking tacky..that's just my opinion...I might be wrong??
Why not keep up simple..less is better?
Cheers

Here is how the abnet works on cleaning.
As I am just starting to work on the bike, a big cleanup is required.
Here are the pictures of the final drive. I honestly didn't spend more than 2 minutes cleaning it.
I sprayed it, and 2 minutes after I took a nylon pad and water to rinse it. Even the oil came off when I rinsed it.

Don't ask about the oil marks on the FD.....
I had removed the speedo sensor and when I put the FD on the bench looking at the open hole, I said OH sh*&$!... I don't have anymore oil. I turned the FD upside down and realized my mistake. I was not looking at the filling hole where oil level should be at the bottom of the thread.

Before

After