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Discussion Starter #1
Pulled the carbs from my T100R and the right hand one was full of this powdery white substance. Left hand one didn't have any. I'm surprised it ran as well as it did. I just started it up for the first time in 5 years and it ran but not with the choke opened. I decided the carbs could probably use some cleaning.
 

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Discussion Starter #2
Zinc oxide? Corrosion of the aluminum from water somehow? Is the carb tanked? Or will something dissolve it?
 

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I had that stuff in my carbs before, too. I assume it’s the residue from what passes for fuel these days drying up in the carbs. I’ve had float bowls with holes eaten through the bottom once I cleaned that stuff out. Try soaking the parts in white vinegar before going further. Any time you aren’t going to ride it for a while drain the fuel from the tank and float bowls or you’ll be doing that same dance.
 

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Hi Eric, My carb looked like that after 34 years of storage. Odd it would only be one. Is that rust on banjo bolt? Maybe had a little water in bowl??

Try submerging in white vinegar. I've found it tends to work quite well. About 20 min at a time, then rise well with hot water. Tooth brush can be useful for scrubbing also.

The harder part is the horizontal passage from bowl feed to idle jet. Vinegar must be forced into this passage to displace any water from rinsing. Compressed air is most helpful.

In any case when cleaning this passage, place a golf T or the like in the idle air intake hole (the small one, not the centered one) at the rear of carb throat. Place fingers over both the tiny floor holes in throat towards front. Now blow compressed air, or carb cleaner into idle mixture screw. It should come out the idle fuel intake hole under carb. This hole lines up with the fuel passage going to bottom of bowl. Then blow opposite, from bottom up to the mixture screw hole. This really helps in clearing the idle fuel passage as there is no direct access without removing the welch plug at rear of carb. I don't like removing that plug.

I've been quite successful with the vinegar if you can force it into the hole while carb is submerged. I take a common soda straw & stick it in the container holding vinegar & carb with carb upside down. The straw will get vinegar in it. Then line up straw with passage & with mouth, gently blow vinegar into passage, but don't blow air. Stop before that.

Using a plastic float with USA fuel can be risky. Any ethanol in the fuel will soften the plastic allowing the tangs to warp & not properly shut off fuel. Amal stayup float kit with viton tipped aluminum needle should be used. Do NOT use brass viton tip needle. Must be aluminum, so shop carefully.

Kits with gasket, float, needle included are sold ebay ect. Or buy float kits & needles separately. Whichever is best cost.
Don
 

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The horizontal tiny jet is a bad design prone to clogging with deposits..On the Amals with the non replaceable pilot jets.....I drill out the jet with something like a .025 drill, blow out the shavings and then screw in the proper sized pilot jet into the existing threaded hole in the top of the float chamber on the main body so it's like the early Concentric carbs.. The jets cost about $5 each and the best part is now you have a tunable low speed circuit and will never have to use a pokey tool to clean the jet....
 

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Hi,

Kits with gasket, float, needle included are sold ebay ect.
Mmmm ... be aware Ebay is where the forgers sell, and some are even stamping "Amal" on jets and printing a similar-looking logo on packaging. :bluduh I always buy either direct from Burlen or at least from a reputable bricks-'n'-mortar dealer; you don't want to be chasing a problem and thinking you've eliminated a possible cause when you're fitting hookey parts ...

The horizontal tiny jet is a bad design prone to clogging with deposits..On the Amals with the non replaceable pilot jets.....I drill out the jet with something like a .025 drill, blow out the shavings and then screw in the proper sized pilot jet into the existing threaded hole in the top of the float chamber on the main body so it's like the early Concentric carbs.. The jets cost about $5 each and the best part is now you have a tunable low speed circuit and will never have to use a pokey tool to clean the jet....
With respect, the "bad design" was evolved when the original Concentric pilot jet location in the underside of the main body was found unsuitable for many 4-strokes. It then worked for years and years without any problem.

Afaict, it more became a problem - like many 'problems' with these old heaps - when they spent less time as their makers intended and more time as garage furniture, around the same time as the agri-businesses worked out there were huge profits to be made from persuading the politicians they could be seen to be Responding To Public Concern About The Environment (aka the media's version of the tree-huggers version of 'science') :rolleyes: by sanctioning the adulteration of vehicle fuel with ever-larger percentages of agri-businesses' products ... :bluduh

If a non-replaceable pilot jet is being drilled out, fit a replaceable jet, which is even easier to access for inspection and any cleaning or tuning?

Regards,
 

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Stuart, I have done it on Triumphs and noticed no problems.. This is my experience..The MK2 also has the pilot jet located on the upper float bowl...Vertical passages are subject to deposits from E10 fuels when they evaporate when the bike is unused for a time, obviously the small jet opening is first to suffer....The vertical jet is less likely to do this ...
 

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My experience with BSA A65 is different, I bought the bike with sleeved early Concentrics with removable jets and it never worked right off idle.
Bought later MK1 with pressed in jets from some Norton owner and it transformed a bike.
I sold a bike 2 years ago, but still hold on to those carbs installed on a small port head as ultimate tuning part for A65 :).
 

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My experience with BSA A65 is different, I bought the bike with sleeved early Concentrics with removable jets and it never worked right off idle.
Bought later MK1 with pressed in jets from some Norton owner and it transformed a bike.
I sold a bike 2 years ago, but still hold on to those carbs installed on a small port head as ultimate tuning part for A65 :).
Sleeved carbs can have off idle problems from the sleeve to slide clearance being too tight.It's a design air leak so to speak. Did you look at the sizing at the removable jets?
 

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Discussion Starter #12
Odd it would only be one. Is that rust on banjo bolt? Maybe had a little water in bowl??
Hi Don,

The left carb had the drain plug removed. I don't know why, but I wish he'd removed the other one too. Yes, that's a little rust. Probably was a little water in there.

In any case the bike came with a couple sets of junked carbs for parts, so I have a good bowl replacement. I'm soaking the body and other parts now. I ordered a couple of rebuild kits off Low Brow Customs, so I should be able to get these back on the bike in a few days.

Thanks everyone for the advice! Great stuff! I'll post my future inevitable questions.

Eric
 

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It's not from ethenol is it? I know if that sits it supposedly turns solid. I don't know, just curious myself.
Many will say so......I saw white crap like that inside carbs years ago before the ethanol invasion..
 

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Discussion Starter #15
It's not from ethenol is it? I know if that sits it supposedly turns solid. I don't know, just curious myself.
I don't think so because the same old gas was also in the tank, but no white powder. I guess it was oxidation of the carb metal from contact with water or ethanol.
 

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Aluminium makes a white deposit anyway. The stuff that carbs are made from is a zinc based stuff and galvanised stuff forms a white residue
As said, it's been around for years and well before ethanol fuel
I have a small ultrasonic cleaner but got most of it out with a green pot scourer before sticking it in

It looks worse than it is
 

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When I found that stuff in my carbs one Spring recently I had used the recommended amount of Stabil in the tank, ran the bike to draw it into the carbs, but did not drain them. I now use SeaFoam, run the bike, then drain the carbs. I usually drain the tank too. No more problems since. No blaming Stabil, nor exonerating them, just reporting events.
 

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Hi Eric,
That’s aluminium oxide. Scrub as much off as possible it is eating the carb away.
You can try boiling it in vinegar for several hours, but it is likely to be tougher than that.
If the acetic acid does not work, The next stage is hydrochloric acid-this is quite dangerous so be careful irf you use it.

Good luck
Peg.
 

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Discussion Starter #20
Thanks for sharing your knowledge and experience, all!

I soaked it in vinegar and wire brushed. The stuff all came off and revealed pitted metal underneath. I'm going to put it back together and see how it works.

Then, I'll keep all this in mind if the bike sits much in the future. But I don't plan on that. :smile2:
 
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