Ariel Owners Motorcycle Club

garycullen wrote: Fri Sep 25, 2026 6:37 am Ha, I love it. I will await the results of your scientific test with interest.
As an aside you never indicated it you managed to get the chrome bolt unscrewed from the carb fuel bowel lid?
They can sometime bind or Gaul up with the Muzak casting.

Thats how it looks, but since it seems to screw in just fine and i'm afraid to snap the alloy when bending it to shape, i'll leave it as is for now. And if it leaks then i'll see what i do.
Thanks for the follow up !

Undo the little hex bolt about a Half turn and then put the cap flat on a solid surface and give the top of the bolt a crack with a hammer. It's been over tightened and deformed. Better not to use it in the first Place. Just tighten the cap sufficiently by the Centre Hex with a 3/8 BS ring spanner.. A new cap is not expensive. Nev

Hello, thanks all for your comments. I've just ordered a new cap just to be on the safe side...

So, the corrosion experiment is officially under way.
However, the idea of putting grease and bits of metal in the kitchen oven at 100°C for several days was received at home with a rather ironic smile, so I took the hint and moved the operation to the sailboat, where i have a gas oven.
What I’m trying to imitate is the basic principle of the ASTM D4048 copper corrosion test for lubricating greases. In the proper test, a clean polished copper strip is immersed in or completely surrounded by the grease and kept at an elevated temperature for a defined period. Afterwards the strip is cleaned and its colour and surface condition are compared with a standard corrosion scale.
The point is to see whether the grease contains additives (particularly certain active sulphur compounds) that react with copper. A good result leaves the copper more or less unchanged or only lightly stained; a bad result can produce strong darkening, black or grey films, staining, and eventually more obvious surface attack.

I’ve used a piece of plumbing copper, which should be reasonably pure, and put it in the SIL GREASE L-EP 00 at around 100°C. The manufacturer actually states a copper corrosion result of Class 1 max. after 24 hours at 100°C, so in theory it should behave well.

The only slight flaw in the plan is that, being a gas oven on a boat, I’m not particularly keen on leaving it running unattended for 24 hours… so this may turn into a rather more hands-on ASTM D4048 than the standard probably intended.

I’ll keep heating it for as long as practical and see whether the copper shows any staining, darkening or obvious attack.

My partner remains unconvinced.

Interesting Albert. I wonder whether doing the experiment with Bronze instead of copper might get you a better result since Bronze sleeves and maybe shims are what is found in BA gearboxes?
Better result as in closer to real world use.
Regarding your oven conflict I had the same with SHMBO when I though I would be crafty and use the domestic oven to release the main bearings from a couple of crank cases. Cleaned it all out but she still smelt that I had done something!!!!

I went and bought a small bench oven that will go to 250 degrees C to now use in the garage.!
one of these:
https://www.thewarehouse.co.nz/p/living ... 91091.html

garycullen wrote: Sun Sep 27, 2026 8:44 pm Interesting Albert. I wonder whether doing the experiment with Bronze instead of copper might get you a better result since Bronze sleeves and maybe shims are what is found in BA gearboxes?
Better result as in closer to real world use.
Regarding your oven conflict I had the same with SHMBO when I though I would be crafty and use the domestic oven to release the main bearings from a couple of crank cases. Cleaned it all out but she still smelt that I had done something!!!!

I went and bought a small bench oven that will go to 250 degrees C to now use in the garage.!
one of these:
https://www.thewarehouse.co.nz/p/living ... 91091.html

Hi Gary, yes, I had exactly the same thought. I actually tried to find the old gearbox bushes so I could test a piece of the actual material, but unfortunately I couldn’t find them.As far as I understand, the BA gearbox bushes were some form of phosphor bronze.
The reason I started with copper is that this is what the standard grease corrosion test uses. ASTM D4048 deliberately uses a polished copper strip as a sensitive indicator of whether the grease contains chemistry capable of attacking copper-bearing materials. If an EP additive contains sufficiently reactive sulphur to aggressively attack the copper component of a bronze, pure copper is actually quite a useful “worst-case detector”, because the copper surface is very sensitive to sulphur compounds. That is presumably one of the reasons the standard uses copper rather than trying to specify one particular bronze alloy.

So my plan now is to use the copper test as the first screening test, and if I can get hold of a suitable piece of phosphor bronze I will put that in the same grease under the same conditions as well. It will not make it a proper ASTM test, but for deciding whether I want this grease anywhere near an 1934 BA gearbox it should be a useful comparison.

For now i'll leave it there soaking for a few days.

And yes… I am beginning to think your small workshop oven was the sensible solution. My partner would probably strongly support that investment after this weekend’s experiment!

Try working on a steam engine. I have a whole wardrobe of clothes that smell of kerosene, and I have to be very careful making sure the washing machine is clean after a day on the footplate!

simon.holyfield wrote: Sun Sep 27, 2026 11:26 pm Try working on a steam engine. I have a whole wardrobe of clothes that smell of kerosene, and I have to be very careful making sure the washing machine is clean after a day on the footplate!

5 and 10" gauge is the biggest i've driven, and after a few hours im black all over the place, so I can imagine a full size! Amazing machines by the way.
..

Sharing some more progress on the fuel tank, a HELL of a job. I managed to clean the tank inside with a cocktail of chemical chelants and weak acids. The tank was covered inside with some terrible pastes and some kind of tar.
I couldnt find anyone that would TIG weld a new tube in. Nobody wanted to risk with the level of corrosion and thinness of the metal.

So i went ahead with epoxy. Some will say it's a botch job but I swear that tube is not going anywhere.
Next step is to apply epoxy inside the tank.

Little Austin a35 looks at the mess from the distance with reluctancy.
BA Gearbox looks in general in good shape, they redid the bushings and replaced several gears so thats ready to come back on together.
I found around the spares what seems to be an electronic charge controller. I don't like that as then could mean that the mechanical regulator is not working properly... so that will need some attention and adjustment too, when the time comes.
I'd like to keep the mechanical, Austin has a very similar one and after some tweaking and adjustments it works perfectly.

Progress on the fuel tank. It has now been epoxied with a couple of layers.
The tank had some leaks which i didnt spot, so hopefully this will seal them