The International CBX Owners Association

hello all,

I want to have my alternator cover chromed in my CBX restoration process. Is there a way to differentiate a magnesium cover Vs an aluminium cover ? Different shade of color ? Different touch ?

I know the 1979 covers can't be chromed as they are made of magnesium.

I bought a '81 CBX but found out many months later that the engine was a '79 according to the serial number stamped on the engine base (to my total disbelief i should say ). The head of the engine was black painted and the rest of the engine was gray. So i'm not sure about the origin of the alternator.

Anyone can give a good advice ?

Thanks

Big6fanatic

big6fanatic wrote:hello all,

I want to have my alternator cover chromed in my CBX restoration process. Is there a way to differentiate a magnesium cover Vs an aluminium cover ? Different shade of color ? Different touch ?

I know the 1979 covers can't be chromed as they are made of magnesium.

I bought a '81 CBX but found out many months later that the engine was a '79 according to the serial number stamped on the engine base (to my total disbelief i should say ). The head of the engine was black painted and the rest of the engine was gray. So i'm not sure about the origin of the alternator.

Anyone can give a good advice ?

Thanks

Big6fanatic

I can't help with the ID, but will offer some free advice you didn't ask for: consider just polishing it.



N.

NilsMenten wrote:[
I can't help with the ID, but will offer some free advice you didn't ask for: consider just polishing it.


N.

Well, that's one way to tell the difference: polish it and let it sit for a week or two. The magnesium cover will turn gray again rather quick.
Also, the magnesium cover will be slightly lighter, if you have an aluminum cover to compare. A kitchen scale will help.
Also look for a possible "casting clock" inside the cover. Sometimes the casters put a date code in the part. It usually shows the year and the month. If it is cast in 1978 or very early 79 it is magnesium.

Great !

Thanks for the good tips guys. Unfortunately, i have no other cover to compare the weight. I also look inside the cover, but didn't find the manufacturing date casted inside. No luck.

Nils: your cover is really nice. Thanks for the pic. My concern is how long will it stays in good shape if i only polish it ? What is your experience on that ? Did you clear coat it ?

big6fanatic wrote:Great !

Thanks for the good tips guys. Unfortunately, i have no other cover to compare the weight. I also look inside the cover, but didn't find the manufacturing date casted inside. No luck.

Nils: your cover is really nice. Thanks for the pic. My concern is how long will it stays in good shape if i only polish it ? What is your experience on that ? Did you clear coat it ?

I didn't. I read differing opinions on this, but the consensus was that in polishing the aluminum the pores of the metal are pretty well closed, and a quick spritz with ProtectAll has kept it looking good so far. Wax was also recommended a few times. HOWEVER: There is no doubt it is not as brilliant is it was right after it was polished. A session with Mothers or something would likely restore it. That's a vote for clear coat if you don't chrome and want it to be brilliant.

It's been only 6 months since it was done, so I'm not the best reference point for how it lasts I'm afraid.

N.

I have two valve covers on my bikes that were polished some 10 years ago. They are still fine without clear coat. The polisher recommended against clearcoating. Especially on parts that go through constant heat cycles. Keep the part clean and polish with a good wax ever so often.

All right guys.

Thanks for sharing your experience and knowledge.

I'll definitely try to polish my alternator cover and see how long it last over time with no clear coat

regards

Big6fanatic

I finally got around to checking my cover(s).

One is aluminum one is magnesium - I looked over both very carefully and there is no
difference you can see . . . . . but the magnesium has allmost a "dull" sound when you
tap on it compaired to the aluminum. (but without both covers its hard to tell)

The magnesium is deffinetly lighter (but again you need both to compare)

Im gonna opt to run the magnesium for the weight - I know the difference is small, but
ounces make pounds on an allready heavy bike.

Bob

MAAS makes a great metal polish protector that will protect a polished surface for a long time.

http://www.maasinc.com/products.aspx

Decided finally to follow Nils' advice and give my best shot to this cover.

Removing 29 years of oxydation was not easy. Started will 240 sand paper, then move to 400, 500, 800, 1000 and 1500. Finished the job with "Mothers"

after 6 hours of rubbing I twisted off a Molson Ex cap !!!

Santé !


As it was



work in progress



once finished

Holy crap, THAT'S what I'm talkin' about! That looks TREMENDOUS! I'll bet your fingers are plenty sore, but from here it looks like it was worth the effort.

Nice work! On to the clutch and crank end covers! ...and the cam end caps....and the footpeg rests...and the brake lever...AAAAIIIIIEEEEEEE!

(for inspiration)



N.

I did a valve cover ONCE. I think i should have clear-coated my fingers before starting. It took a long time for the dirt and grime to disappear.
Your cover looks great, big6. I am guessing there was more than one Ex cap twisted.

If you use Aircraft Stripper before you start polishing, it will make things a little easier. It will take off the clearcoat and will get you to the bare aluminum quicker.

EMS wrote:If you use Aircraft Stripper before you start polishing, it will make things a little easier. It will take off the clearcoat and will get you to the bare aluminum quicker.

+ 1

Bob

zxbob wrote:

EMS wrote:If you use Aircraft Stripper before you start polishing, it will make things a little easier. It will take off the clearcoat and will get you to the bare aluminum quicker.

+ 1

Bob

Well guess what ? The clear coat was all vanished with time. Only the size of a quater was remaining which was easilly removed with a good stripper. That's why the cover was in so bad shape at the start.

But thanks for the hint anyway

Big6