Polishing the engine casing

I have seen posts regarding this several times, but they were far in depth for the most part and included instructions and tools that I have not used. Honestly I do now know a lot about bikes, technically or otherwise. That is why i'm here--to learn more.

What is a quick way to polish the aluminum engine casing and other metal parts on my bike? I am not confident in taking the casings off or anything like that, I just want to do the best I can without removing anything. I might be buying a 1982 KZ550 LTD today so long as my dad and I can't find anything wrong with it. If I do get it I am looking forward to doing some cosmetic work on this bike.

Thanks for any help I can get.


C. Tupper
Spokane, Wa
[maybe] 1982 KZ550 Ltd

The engine (at least the outside) is made entirely of aluminum.
Some to the parts are 'cast', and some are 'machined'.
The cast parts are rough, and can be cleaned and brighted, but will never shine like chrome.
The machined parts have (or had) a smooth surface, and, with time and effort can shine like chrome.

So, clean the engine with a de-greaser and a stiff brush. I like Simple Green.

For cast parts (like the cooling fins): Use a scotchbrite pad dipped in Mothers Aluminum Polish. Rub it on. The paste will turn black. Wipe with a clean cloth. The more you do, the better it will look.

For the machined parts (like the timing plate cover): If it's still smooth, and not pitted or scratched, try Semichrome. Rub it on with a soft cloth, it turns black, and buff it off.

Engine polishing is something to do when you have time, and it's too cold or wet to ride. Grab a stool, some tunes, and some cold beer. An hour here and there will pay off.

Good luck.

Post edited by: ltdrider, at: 2006/07/24 13:50

thanks a lot, that was helpful. I have to say I am quite excited with the prospect of getting this bike. When I first saw it I thought to myself that it was a little too old looking, but then being on this site for a while I saw what I could do to it, and how the cosmetic issues can be fixed with a little work and a bit of money. And after that these KZ bikes are some of the best looking ones out there. I have never done anything more than put a coat of polish on my 250 REbel, and that was without knowing what I was doing, so I look forward to learning how to fix up this bike.


C. Tupper

I like WD-40 and fine steel wool. It really does just take time, elbow grease, and inventive ways to wrap your abrasive around popsicle sticks to reach between the fins...

that '82 550 ltd will have a coating on the cooling fins and cam covers, polishing wont help em one bit, all you can do is clean em up. However, the ignition cover, sprocket cover, clutch cover, and stator cover are all very easily polishable. I wetsanded mine with a bit of 800 grit wet or dry sandpaper with watered down simple green for the water, then repeated with 1500 grit and 2000 grit, followed by a good rub down with mothers mag and aluminum polish.

Everything you need right here.
www.caswellplating.com/buffs/alpolkit.htm
They've got a how-to,and a forum devoted to metal finishing. Careful,I've found out that polishing can be highly addictive.:laugh:

Mothers polish is the sh*t, gotta agree with ltdrider on the tunes stool and beer. More you rub cleaner she will be.

I thought that Muthers Al. Polish and 000 fine steel wool worked great, and pretty fast. My covers were removed from the bike when I first did them, but touch-ups on the bike are easy too. Check the link in my signature, eventually you can find some before and after pictures (I really should take more pictures and organize!)

sos soap pads are really good for severly oxidized aluminum...dont get too aggressive with them, just enough pressure to remove the nasties, then rinse thouroughly, then follow up with a good polish and lots of elbow grease...before you know it you have nice shiny aluminum again (and a sore arm!! :ohmy: :laugh: )

heartless wrote:

sos soap pads are really good for severly oxidized aluminum...dont get too aggressive with them, just enough pressure to remove the nasties, then rinse thouroughly, then follow up with a good polish and lots of elbow grease...before you know it you have nice shiny aluminum again (and a sore arm!! :ohmy: :laugh: )

Whats an sos soap pad and where can I find one?

I bought some of that mothers wax and just to see what would happen, i did a little buffing on my already dirty/dull engine casing and definitely the mothers looks like it will give me good results since right away things were looking shinier. Want to get my engine sparkling though, or at least pit free and kinda shiny

securitygeek...what paint did you use on the jugs and valve assemblies? Was the engine out when you did this?

Hello All,

A few weeks ago I bought my first real bike. It's a 1977 KZ650B. It's in pretty good shape and I'm planing on turning it into a Cruiser. There is a bunch of good information here and I thought I'd help contribute to the cause.

Well I found a little time today to start polishing my engine cases. They are pretty oxidized and there is a small amount of rash on them. Here is what they looked like before I started on them.



As you can see they weren't very pretty. I started with a fine flat file. I used the file only on the bad areas. These took the most time. If you do this get a file card and keep your file clean or you will put more scratches in the case that will have to be sanded out.



I have the top part of the clutch case cleaned almost up. When I started to sand I could see the spots that need to be filed a bit more so I would stop and file those spots then continue to sand. The sand paper I am using is 220 grit wet dry paper I picked up at Wally world.



I think they are coming along pretty nice. This took me about a beer and a half to do. A six pack should take care of it. After I get it all sanded with the 220 grit I'll move to the 300 then the 400. I should be able to polish it then. I tried to polish a small spot with the Mothers and the oxidation was to deep. I would suggest sanding the oxidation away.

After I get these polished, I'll install the brand new case guards that just showed up. This will help protect my hard work