Leaking carbs and help with fuel lines

[taibhse]

Hello everybody, sorry if this was posted already, but the threads I've been able to find are old ones and pics can't be viewed anymore, or don't have the information I need, and can't find anywhere.

First a bit of context. I took the tank and mudguards to get painted, and my mechanic left gas in the carbs for 3 months, so it turned into jelly.

He allegedly cleaned the carbs before, these were in perfect condition, mechanically the bike was running flawlessly with no issues before all this.

When I got it back I used it 2 days, and then it started leaking an awful amount of gas through the air filters, to the extent that overnight a full tank was emptied.

I ook off the carbs, opened them up and cleaned them. After that everything looks fine, but when I reassembled the bike it started leaking again. Not drops, I just gushed out the air filters.

Now my question is this, could it be due to the fuel lines are being misplaced? I'm aware that these carbs work by vacuum, so I'm worried that there's a part of the fuel circuit that might not be complete or that I might have hooked them up to the wrong nozzles.

There are 3 hoses coming out of the tank. 2 on the tank nozzle (a small one and a big one), and one on the opposite side of the tank (a big one).

The carbs have 4 places where they can go plugged in. First on top of the carbs on the external sides, 1 on each carb, while the one on the right carb is capped (has a plug on it).

One that connects both carbs horizontally and that has a small nozzle in the middle (T shaped), and one under the carbs that also connects both carbs horizontally, towards the rear, near the air pods, that has a nozzle on the left side of the connection (it's also T shapped, but the nozzle is on the left side instead of in the middle like the one between the carbs).

The only two hoses that were connected were the ones that come out of the tank nozzle. I hooked up the smaller line to the nozzle on the top of the left carb.
The big one to the line that connects the carbs with the nozzle in the middle (The T shaped one).

And the big one that comes out of the right side of the tank, is not connected to anything.

Is that how it should be? Or should the one that isn't connected be connected to the carbs too?

Sry if i'm not clear enough, I'd be glad to clarify if needed.

[Blaine]

Too make this simple the fuel inlet is the bottom T (fuel hose from petcock goes on there)......The upper T is a vent/overflow & must remain open...I believe this is your problem the fuel hose got put on the upper T

[taibhse]

Thank you very much!
Yeah. I made that mistake.
Does the smaller line that comes out of the fuel tap go to the left carb?

[Blaine]

Yes...That is the vacuum for the petcock.

[andyuk454ltdbiker]

Apr 18, 2020 21:56:33 GMT -6 Blaine said:

Too make this simple the fuel inlet is the bottom T (fuel hose from petcock goes on there)......The upper T is a vent/overflow & must remain open...I believe this is your problem the fuel hose got put on the upper T

I do not understand exactly what you mean. I did a little basic drawing of the issue.

We have 3 pipes.

Pip A it at the top front (facing the Engine)

Pipe B back bottom

Pip C top Middle.

The sizes of the pipes would suggest that Pipe A goes to the small pipe connection of the Petcock, Pipe B goes to the Large pipe connection on the Petcock, and Pipe C goes to the right side Large pipe connector.

Yes I know my picture isn't great but to me it may explain a lot when you can actually see whats what.



I am trying to rebuild the carb from scratch and have no experience with CV carbs. 

Any and all advice would be great, at the moment I have my engine running on one cylinder as the other is just not firing correctly. I do not have a spark issue, power issue or anything like that, and I do believe it is a fuel related issue because the right cylinder seems to be starved of fuel where as the right side runs perfectly ok when running on its own. I really need to figure out whats going on. All new jets and needles, also new gaskets on both carbs.

Engine pressure is good.

[Blaine]

you are correct except for pipe C (upper T)....It is a vent /overflow & must remain open & unpluged......It should have a clear hose on it that exits out by airbox.

[andyuk454ltdbiker]

That's good then. I have everything in the right places. The clear pip go's exactly where you said, I am just having what looks to be a fuel starvation problem, but getting it to run correctly is a problem. It was running perfect until I had it standing for a while, which couldn't be helped. It is all road worthy and runs perfectly on the tick over, just when I throttle back it just sucks in air and dies.

Stripping the carb back again tomorrow and will see what is going on, I have new needles and everything on it do it does not make any sense.

[steamy]

Dont know if this helps, but... I had a mud dauber crawl up my vent hose and make a mud nest at the end of the metal tee inside the carb. There was a dead dauber that I had to pick out peice by peice with long needle nose pliers. They have done similar to my boat motors p hole.