[Thederustinator]

Hi

New here, so hi everyone.
I stripped my 1050 St down to tidy it up a bit and it has left me with a couple of questions:-
I aggressively cleaned the corrosion off the front wheel, rear wheel, swing arm, but the subframe is particularly bad. I got the paint off and the corrosion is all over the tubes, but none on the end bungs, welds or flat brace, I guess the tubes are.... of a different material with zero corrosion resistance, probably high in magnesium. Does anyone make a decent replacement for the subframe with a better corrosion resistance?
The other issue, (same one as with the 955 ST/RS SSSA), is the swing arm / shock linkage spacer - the rusty steel one that bolts to the arm itself. I used heat and a puller to try and pull it out, but it snapped. I have a new one on its way, but how do I stop it rusting itself together again? Has anyone found a cure - paint it perhaps?
These questions are probably are as old as the triumph is, so apologies if they have been answered before, I just can't find the answers.

 

[Thederustinator]

 

[Thederustinator]

 

[Thederustinator]

Lobbed the drag link on the bonfire and got the spacer out. I had to cut the bearings out. I have built up a boss in the middle of the round bit, and drilled and tapped it for a grease nipple - the other part of the linkage is Aluminium and may well warp if I try to weld a boss in that part. Subframe corrosion is an issue, because of the alloy used. It is very poor at corrosion resistance, and most inhibitors are for steel. I tried an acid cleaner, which surprisingly made things worse. Next step will be sampling Cortanin F rust treatment to see if that works with this particular alloy, if not, it will be Zinc primer, then Henry Coles favourite paint.

 

[fredsprint]

View attachment 750756

For this one phosphoric acid bath (50% water 50% acid) is the way to go. The bearings should be removed first.
If you can't remove the bearings then white vinegar bath for one or two days should ease up the process.
Then epoxy coating.

 

[Little Miss Murder]

Is this not possibly a galvanic corrosion issue?

 

[Thederustinator]

On the subframe, the pannier brackets rotted because stainless bolts were used, but the subframe is made from 2 types of Aluminium, the tubes being alloyed with silicon and magnesium, the solid parts less exotic. I guess there will be a reaction between the magnesium and the aluminium on the surface of the tubes, but the question is how to stop it. It only takes one chip for corrosion to get in and it goes unseen until the paint / plastic coating falls off. Jap bikes use less exotic alloys and they anodise the tubing, but this is not possible on magnesium.
The only real way to stop it I guess, would be to make a new one out of material more suited to use on a road bike.
As for the steel lump of rust, left it in a bucket of acid for a while, and it is now clean under the zinc paint and hammerite smooth black.

 

[Little Miss Murder]

Make sacrificial anode plates XD. Hey, it's an idea.

 

[Thederustinator]

Make sacrificial anode plates XD. Hey, it's an idea.

funny you mention that, I have a big lump of zinc I could use for the steel parts, but not so good for the magnesium