Ultrasonic cleaning - a cautionary tale

[RogerE]

I had the carbs on my S2 ultrasonically cleaned this week and they looked great. However, the guy that did them called me a day later and said that he had found some small brass balls (2 mm and 4mm) in the tank afterwards. I said I wasn't aware of them as a component of my carbs, but hang on to them all the same...…

When I put the carbs back on today, as soon as I turned on the fuel tap, petrol gushed all over the engine! The cleaning had dislodged the small, 2mm brass ball that seals what seems to be a redundant outlet just below brass pipe where the fuel enters (see attached picture). It had also detached a larger, 4mm brass ball near the choke that must perform a similar function.

20200429_132849.jpg

I have no idea why these seemingly redundant features are on the carbs, does anybody know why? Anyway, if you do get your carbs ultrasonically cleaned, examine them very carefully after!

[ACS International]

Hi,
I think you'll find the balls are to block drillings that are done in the manufacturing process
of the carb.
I guess you could refit the balls and smear araldite, or other epoxy glue, over the outside to seal the ball.
Hope this helps
Ade

[RogerE]

Thanks for the reply - I am waiting for the Araldite to set now!

Roger

[Craig T]

Not sure about Araldite and petrol together long term....could degrade.
I'd try and get a mechanical fix too (peen over the alloy) just in case the Araldite gives up.
Brilliant article by Dave Higgs in the resources section on carbs.

[Hal]

The Araldite will be fine. I made a temporary repair to my H2 tank where they commonly fail by the strap bracket, and it stayed put for years with no problem.

[h2bchris]

[quote="RogerE"]I had the carbs on my S2 ultrasonically cleaned this week and they looked great. However, the guy that did them called me a day later and said that he had found some small brass balls (2 mm and 4mm) in the tank afterwards. I said I wasn't aware of them as a component of my carbs, but hang on to them all the same...…

When I put the carbs back on today, as soon as I turned on the fuel tap, petrol gushed all over the engine! The cleaning had dislodged the small, 2mm brass ball that seals what seems to be a redundant outlet just below brass pipe where the fuel enters (see attached picture). It had also detached a larger, 4mm brass ball near the choke that must perform a similar function.

20200429_132849.jpg

I have no idea why these seemingly redundant features are on the carbs, does anybody know why? Anyway, if you do get your carbs ultrasonically cleaned, examine them very carefully after![ Thanks for the warning

[Doctorpayday]

Try tapping holes out to accept short grub screws and loctite them in.

Doc

[RogerE]

Thanks for the useful advice. I did a bit of investigation and araldite should be ok, but I will keep a close eye on it. I filled a tiny hole on the underside of an exhaust with araldite and that has been fine for years and that is subject to petrol/oil gunge and some heat.

Products called Chemical Metal and JB-weld sound like the best stuff to use though.

Roger

[mraxl]

The same thing can happen to the intakes.... and where the ball goes depends on which side carb you have...

[Triple Parts]

JB Weld is great stuff.

[RogerE]

Thanks, great pictures mraxi, I'll check if those balls are still there!