Topic: Carbs Leaking Fuel After Rebuild

[jetthugo]

Also found this slit in the hose, would that cause a leak???


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[minimo]

Those are the fuel overflow hoses.

The petcock ON should not make your fuel leak. The floats, when adjusted correctly, will stop the incoming flow of fuel to prevent an overfill situation.

Have you adjusted float heights correctly?


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[jetthugo]

Those are the fuel overflow hoses.

The petcock ON should not make your fuel leak. The floats, when adjusted correctly, will stop the incoming flow of fuel to prevent an overfill situation.

Have you adjusted float heights correctly?


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So I read online to adjust the floats to about 23mm which I didn’t. 3 of the carbs stopped leaking while one of them still slightly leaks. I’m debating if I should bump that one up to 24mm. I ordered an air compressor online to do the measuring trick so still waiting on that.


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[minimo]

21mm should be the correct height.


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[Robbo]

Those are the fuel overflow hoses.

The petcock ON should not make your fuel leak. The floats, when adjusted correctly, will stop the incoming flow of fuel to prevent an overfill situation.

Have you adjusted float heights correctly?


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So I read online to adjust the floats to about 23mm which I didn’t. 3 of the carbs stopped leaking while one of them still slightly leaks. I’m debating if I should bump that one up to 24mm. I ordered an air compressor online to do the measuring trick so still waiting on that.


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Swap the float from the carb that still leaks with one that doesn’t leak.
If the leak moves to the other carb, then the float needs further adjustment.
If the leak stays with the original carb, it could be a faulty float needle or cracked overflow tube.

Hint:  move the float to a carb at the end of the rack so you have easy access to adjust the float.


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[jetthugo]

So I put the measurements of the floats back to 21mm from 23mm and now they’re all leaking again. I’ll put them back at 23mm and swap the leaking carb float with another to see if that leaks too.


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[minimo]

Just curious, are you using aftermarket float valves? Those tend to be finicky. If you have OEM, clean them up real good or ultrasonic bathe them.

I’m curious how you are measuring the heights


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[jetthugo]

Just curious, are you using aftermarket float valves? Those tend to be finicky. If you have OEM, clean them up real good or ultrasonic bathe them.

I’m curious how you are measuring the heights


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Yea I was using some aftermarket float valves, I noticed they were a little longer than the original ones I had on. So I cleaned those and put them back on the back. Good news, no leaks! But a new problem, the bike turns over but won’t start.


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[minimo]

Turns over, but won’t start?
Do you mean that it won’t stay on?
Check the plugs. Are they wet?

Also, with all the fuss with your floats, now, how many turns out from full seated are your air/fuel mix screws?

[jetthugo]

Turns over, but won’t start?
Do you mean that it won’t stay on?
Check the plugs. Are they wet?

Also, with all the fuss with your floats, now, how many turns out from full seated are your air/fuel mix screws?

Bike just squeaks but won’t start. Plugs are good, not wet. Air/fuel mix screws are turn out 1 1/2 turns. Is that right?


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[minimo]

Any update? Does your tank have fuel?


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[roach374]

Start from the tank: Does it have fuel? Then the petcock, is it open? Then the carbs, are the floats "stuck" up, closing the needle valve? Is the choke on?

If the plugs aren't wet, it suggests the engine isn't getting any fuel.

[jetthugo]

Hey guys sorry for the hiatus, life had me busy. Anyways I got everything back on the bike with the float bowls right. Bike turns on but will shut off once I pull the throttle. If the choke is open, the bike will run. Oil is also spitting from the exhaust while this happens. Not sure what to do from here.


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[evinrude7]

Coming back to this with another question, are the carbs supposed to overflow and leak worthy the petcock on?


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not supposed to overflow at all. 

[jetthugo]

Coming back to this with another question, are the carbs supposed to overflow and leak worthy the petcock on?


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not supposed to overflow at all.

Yea the floats were getting stuck, fixed that and no more overflow. Problem now is that the bike won’t run without the choke being open.


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[minimo]

Good thing you were able to get your floats to not stick. Now, “Choke being open”? Do you mean choke ON, so, flaps down? If so, this might mean that you need more fuel, which is why you have to trim the air flow. Oh, the fun begins


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[jetthugo]

Good thing you were able to get your floats to not stick. Now, “Choke being open”? Do you mean choke ON, so, flaps down? If so, this might mean that you need more fuel, which is why you have to trim the air flow. Oh, the fun begins


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Ohh ok that could be the issue. Sorry yes I meant choke ON. I don’t have much fuel on at the moment since the carbs were leaking and I learned my lesson to not fill up the bikes tank to full. I’ll add some more fuel and see what happens. Would that explain fuel droplets flying from the exhausts?


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[jetthugo]

Update. Added some more fuel. Same problem, dies with choke on/open.


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[minimo]

Just say, Choke ON


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[minimo]

How are your plugs looking too, btw? Can you snap a pic?


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[jetthugo]

(null)
You’re right. Choke on.


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[jetthugo]

How are your plugs looking too, btw? Can you snap a pic?


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Plugs are looking good. Had replaced them before I did the carb rebuild and they’re still looking good. I have a feeling that there might be a collection of issues that need to be fixed. I spent almost a grand having the bike tuned up and decided not to use it until 3 years later since I had a few other bikes I was using. Not sure if the last mechanic gave the bike a thorough look because I remember it still not riding right. I found someone nearby who specializes in classic Honda’s so I might just take it to him to make the bike run even better to how it was running before with some updated parts. That’ll be next week so I’m sure I’ll still mess around with the bike until then. At this point, not sure what the problem could be with the bike at the moment. Thanks for everyone’s tips and help! Greatly appreciate it!


(Minimo, I’ll snap a pic tomorrow of the plugs when the suns out and post it!)

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[minimo]

Now that you’re not getting overflow leaks, something about your carbs is starving it of fuel, which is likely why it can only run with Choke ON (limiting the flow of air). What air filter(s) are you running?

- Check your fuel cap vent
- Check your petcock (may need a cleaning too) and any inline fuel filters and lines
- Check for anything else that may inhibit the flow of fuel to your carbs

Btw, did you say that you got around to performing the air hiss test? Or a fuel level test?




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[jetthugo]

Now that you’re not getting overflow leaks, something about your carbs is starving it of fuel, which is likely why it can only run with Choke ON (limiting the flow of air). What air filter(s) are you running?

- Check your fuel cap vent
- Check your petcock (may need a cleaning too) and any inline fuel filters and lines
- Check for anything else that may inhibit the flow of fuel to your carbs

Btw, did you say that you got around to performing the air hiss test? Or a fuel level test?




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So the fuel cap WAS leaking fuel so I replaced the gasket, so now it’s doesn’t leak. I rebuilt the petcock with a kit I purchased from 4into1. Made sure that was installed correctly and should be good. I never did a air hiss test or fuel level test. One thing I should mention thought is that the tank, since sitting for almost 3 years, did have some flash rust in it. I cleaned it out twice with the vinegar trick. I can’t stop thinking that the tank still isn’t completely clean and has some sediment on the bottom that is clogging up the petcock.


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[minimo]

Well, then all of those things then are still possible culprits to the apparent carb issues that you’re having.

I’d check the flow of your petcock to make sure that it is flowing.

Turn off your petcock and connect a separate short fuel line to it and redirect it to a jar or other reservoir - make sure to set it at a level lower than the petcock (gravity). How does it come out? If it trickles, there’s likely a clog. If it flows like a wild willy, move on to the next possible issue


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