Carbs are disolving alloy bungs!!! HELP

[daveb]

Firstly hi everyone I am new to the forum I have an issue with the alloy bungs in my carb bodies disolving, the bike had been stood for a few years when I got it so I stripped and ultrasonically cleaned them before re fitting them, all looked fine until i put them back on the bike and it ran very rough so I looked in the carbs and all 4 were doing the same thing (pic B) has anyone come across this before? Can i replace them? Any help much appreciated. Thanks Dave.

 

[Fire-medic]

Is that a Q-Tip or a terrycloth rag?

Looks like you have a torn gasket for the jet block mounting, which will cause issues in operation. Any time I remove a jet block, replacement of that gasket is usually something I do as a matter of course. That and the needle valve, which you can buy from K&L.

I don't recall ever having to remove that bung.

 

[daveb]

Is that a Q-Tip or a terrycloth rag?

Looks like you have a torn gasket for the jet block mounting, which will cause issues in operation. Any time I remove a jet block, replacement of that gasket is usually something I do as a matter of course. That and the needle valve, which you can buy from K&L.

I don't recall ever having to remove that bung.

Hi, Thanks for the input, I replaced the jet block gasket, that white stuff is the bung itself disolving, really baffeled by it? It is happening in all 4 carbs the same.

 

[02GF74]

I've had my carbs apart twice (98 model) and didn't notice anything like that.

Maybe a previous owner poked around inside and replaced the bungs with a base metal that is not resistant to petrol or maybe yamaha used an inferior part.

I don't know the purpose of these and if it is a simple shape, try to get some made up from brass to replace them.

 

[Fire-medic]

I've never seen anything like that. Ask dannymax, CaptainKyle, and Sean Morley.

I believe chlorine is harmful to aluminum, maybe someone tried cleaning the carbs with some pool cleaner they had.

 

[gentsvmax]

Firstly hi everyone I am new to the forum I have an issue with the alloy bungs in my carb bodies disolving, the bike had been stood for a few years when I got it so I stripped and ultrasonically cleaned them before re fitting them, all looked fine until i put them back on the bike and it ran very rough so I looked in the carbs and all 4 were doing the same thing (pic B) has anyone come across this before? Can i replace them? Any help much appreciated. Thanks Dave.View attachment 84317View attachment 84318View attachment 84319

Yea! That's how you do it, great pics get you great help!

 

[dannymax]

Never saw anything like that before. Is that fuzzy stuff in the second photo firm or does it turn to powder when disturbed?

 

[DreamV4]

sаnd them and cover with fuel tank repair epoxy, I would

 

[daveb]

Never saw anything like that before. Is that fuzzy stuff in the second photo firm or does it turn to powder when disturbed?

Hi Danny, It feels like talkum powder, it is like an alkaseltzer fizzing.

 

[Fire-medic]

OK, I would immerse them in a solution of plain-old H20 and a 1 lb box of sodium bicarbonate. Let's try to stabilize whatever ph issues are happening. I'd disassemble them into individual pieces, instead of what I usually do, into two pairs.

First remove the coasting enrichment valve cover (contains parts in #19) and the starter body (#24) and of course the float bowl and the jet block. This is p. 5-1 in the shop manual. Chapter 5 is Carburetion.

VMX12- Service-Manual.pdf (vmoa.net)

 

[CaptainKyle]

I have never seen that happen before

 

[maleko89]

Hi Danny, It feels like talkum powder, it is like an alkaseltzer fizzing.

I remember someone using CLR as a carb cleaner and turned powdery like that.

 

[daveb]

Thanks again for all the input everyone, this is what i did with the carbs just so you all know. I have a 6L ultrasonic tank and I used an eggcup full of carb cleaner to 6L of de-ionised water ( Temp was 55 deg ) as I know too much cleaner can turn carbs a horrible dark grey, I have cleaned loads of carbs this way with great results. I have added pictures of the cleaner used and the Vmax carb components stripped out of the boddies, all parts that were cleaned were then rinsed in luke warm water and dried before reassembly, once fully assembled they looked great with no visible problems or the fizzing alloy you see in the pics above, the carbs were left a couple of weeks in a dry environment untill I got time to refit them and when E5 unleaded fuel was added to the system the problem started in all 4 carbs at the same time and that is where we are now? Thanks Dave.

 

[dannymax]

I don't see the bleed pipes or pfj's...you need to remove them from the jet blocks for a complete cleaning...especially the pfj's.

 

[02GF74]

too much cleaner can turn carbs a horrible dark grey,

I was wondering why your carbs were that colour.

Re; sodium bicarbonate aka baking soda - are you sure? since a solution attacks aluminium - I expect the carbs to be aluminium alloy castings.

 

[daveb]

I was wondering why your carbs were that colour.

Re; sodium bicarbonate aka baking soda - are you sure? since a solution attacks aluminium - I expect the carbs to be aluminium alloy castings.

The carb picture with the red arrow was taken off the internet and used for ref only to show the part I am describing

 

[dannymax]

Not picking your stuff apart but the plastic cut-off cover goes on the #4 carb, not #1
carb numbering:

front
2 4

1 3

 

[daveb]

Not picking your stuff apart but the plastic cut-off cover goes on the #4 carb, not #1
carb numbering:

front
2 4

1 3

No problem Danny, thats just the way i numbered them, they all went back together as they should. Cheers Dave.

 

[dannymax]

Did you replace the plugs?