Magnesium rot...

[pmcburney]

I opened the can of worms on the weekend.


Not content to let sleeping dogs lie, I popped the cover off the waterpump of my newly acquired '86 500 on Sunday morning only to discover a fairly advanced case of corrosion within (even though it had been painted or coated or such like).

Now, as it happens, I've sourced a new LH engine cover and I want to mitigate the corrosion in this cover as much as possible.
What has anyone else tried in the way of any coating or other procedure in their cover to prevent or curtail the dreaded rot?

I've been told the anti-corrosive coatings this mob make are very good, but I'm curious to know what else has been tried.

Any info greatly appreciated.

[Slakewell]

Run little or no water will help

[firko]

What were Honda (and other makes) thinking, making mag water pump housings and cases? Magnesiums worst enemy is moisture and general weather oxidation so why use magnesium in parts that are open to moisture. The weight saving isn't that much. I've been cleaning out my parts stash garden shed this very morning and found a mag CZ front hub that had fallen off the rack and been laying on the concrete floor for maybe 3 or 4 years. I couldn't believe the oxidation that had taken over it....there's no way I'd use the hub and feel safe.

Somebody told me of an anodizing like process but I don't know the details.

[Freakshow]

COVER THE INTERNAL AREA WITH kREeM, PORS OR SIMILAR. then its impervious to the moisture and can still breathe from the outside

[Mike52]

HANG ON.
Is this the 500 you bought off ebay PCM?
Didn,t that guy say that he had fitted a reconditioned clutch cover ?
First thing I,d do is to give him a ring.

[pmcburney]

HANG ON.
Is this the 500 you bought off ebay PCM?
Didn,t that guy say that he had fitted a reconditioned clutch cover ?
First thing I,d do is to give him a ring.

Yup, that's the one.


And, well, the cover has been reconditioned - it has a coating applied to the area where the waterpump lives.

However, it's not that great a job.
It looks like Cream or a similar product and it either wasn't applied properly or it just isn't up to the task as it's flaking off (leaving behind bare magnesium which is disappearing real quick) and filling my radiators with chunks of gelatinous crap.

The cover is still serviceable as there is still a fair amount of metal left before it will go through or collapse completely, but it won't last forever.

I've bought a new cover from Magic Racing in the States for US$220.00, so in reality it's not that expensive to fix (replace). I doubt I could repair the cover I have for much less than that.

But... the new cover will need to be either coated/protected or I'm going to have to use a non-corrosive coolant.

BTW, does anyone have any leads on someone who can do a stainless insert for these things?
I'm sure I was talking to Brad (Lewis) about this and he reckons they can be sleeved, which should then sort the issue for good.

Oh, and there's been a water leak into the gearbox at some stage on this bike - there's a lovely distinct corrosion line across the bottom 1/3 of the clutch and the nut holding the crankshaft gear is rusty.
Let's hope the bearings and gears in the 'box are ok.

Bloody old shitbox dirtbikes...