Just what IS in US fuel???

modelman · Post by **modelman** » Fri Jul 03, 2015 6:51 am

1965 305 superhawk, US to UK import.

Been standing for god knows how long, seized solid!!

But we're getting there, dismantled petcock, bowl full of white powder, cleaned it out only to find several holes where whatever it was, 'dissolved' the die-cast alloy.
Then, removed the carb bowls to find a teaspoon full of same white powder, BUT, this time the floats have 'dissolved'......... EH???
Just what DO you guys have in your fuel??
I've restored many old jap & UK bikes, (Suzuki, Triumph, BSA, Norton etc.) & never come across this phenomenon, Any thoughts?
Is it micky-mouse metal? or the fuel?
Suggestions as to best way to clean the carbs, I have an ultrasonic cleaning tank, but not sure what fluid to use or even if it will remove this 'stuff'.
Or is there anything that will dissolve this as its everywhere in the carbs.

Hahnda · Post by **Hahnda** » Fri Jul 03, 2015 10:52 pm

I have seen that in a few different carbs. The latest one was an Amal off a 441 Victor. No idea what is the cause though. It actually gets to areas that aren't even submerged in fuel. The top of the float chamber wouldn't have been submerged but I guess when the fuel evaporated it still left deposits. Its very hard to clean up. I have ran them through ultrasonic and regular carb cleaner followed up with manual scraping. Soda blasting will take care of some of it but only after most of it is gone. I have also had one vapor blasted and that worked the best.

DCON · Post by **DCON** » Sat Jul 04, 2015 6:56 am

Welcome to our world!!
Sorry, it's horrible stuff. Sometimes it eats pinholes through the carb body itself.
The best thing I have found to dissolve it is penetrating oil. Made my last job
Much faster on a kids bike that sat for two years.
I e used two brands of spray can penetrating oil and both worked well. 'Merica

LOUD MOUSE · Post by **LOUD MOUSE** » Sat Jul 04, 2015 12:11 pm

Soak it in vinegar. .............lm

DCON wrote:Welcome to our world!!
Sorry, it's horrible stuff. Sometimes it eats pinholes through the carb body itself.
The best thing I have found to dissolve it is penetrating oil. Made my last job
Much faster on a kids bike that sat for two years.
I e used two brands of spray can penetrating oil and both worked well. 'Merica

modelman · Post by **modelman** » Sun Jul 05, 2015 3:01 am

Well after soaking in the ultrasonic tank for many duty-cycles & at the hottest temp, (too hot to touch) the carbs have come up like new, revealing holes in the float-bowl, managed to remove all the brass screws, plugs, jets etc. EXCEPT the main? jet at the bottom of the lower hole in the pic above.
I don't think any of this stuff has ever been removed from new as all the brass hexagons, screw slots are perfect, with the body held secure, a good fitting screwdriver was applied, tapped, twisted with a vise-grip on the handle, but still no, I have the feeling that I'm close to shearing the top off.
Replacements seem to be like rocking-horse s**t,
SO, I think for the time being, a replacement set of carbs will be required, I've read on this forum that 26mm Amal concentrics can be used, would that be the bog-standard 'basic' handed units??
I see from the specs that they have 2" (50mm) flange-hole centres as against 48mm of the originals, I can mill these 1 mm each to 'adjust' the fitting.
Also, they seem a bit taller, any issues with that?

LOUD MOUSE · Post by **LOUD MOUSE** » Sun Jul 05, 2015 5:48 am

This may be difficult for some to believe!
That stuff was caused by having WATER in therefor a LONG TIME.
If you find this stuff again Vinegar will remove it. ....................lm

modelman wrote:Well after soaking in the ultrasonic tank for many duty-cycles & at the hottest temp, (too hot to touch) the carbs have come up like new, revealing holes in the float-bowl, managed to remove all the brass screws, plugs, jets etc. EXCEPT the main? jet at the bottom of the lower hole in the pic above.
I don't think any of this stuff has ever been removed from new as all the brass hexagons, screw slots are perfect, with the body held secure, a good fitting screwdriver was applied, tapped, twisted with a vise-grip on the handle, but still no, I have the feeling that I'm close to shearing the top off.
Replacements seem to be like rocking-horse s**t,
SO, I think for the time being, a replacement set of carbs will be required, I've read on this forum that 26mm Amal concentrics can be used, would that be the bog-standard 'basic' handed units??
I see from the specs that they have 2" (50mm) flange-hole centres as against 48mm of the originals, I can mill these 1 mm each to 'adjust' the fitting.
Also, they seem a bit taller, any issues with that?

modelman · Post by **modelman** » Sun Jul 05, 2015 6:41 am

OK, thanks for that, everything is now soaking in vinegar, watch this space!!!!!