B12 leaky float

[sk1200]

Hey Suzuki lovers! Came hoping to pick your brains as a last resort in my struggle with a leaky float.

 

I have a leaky no.3 carb float on my mk1 Bandit 1200 - fuel is going through the left of the two airholes. I replaced the seat, needle and the float iself with new parts, set the float height to 14.6mm as per the Manual. When I drop the bowl, let fuel in and close the float with my finger lightly, no leak, but when I close the bowl and let fuel in to do the same job, it leaks. I tried swapping the seat, needle and float with no 4. carb, and no. 3 still leaks unless I close it with my finger. Have I perhaps overlooked something? 

 

Wife and I are hoping to get riding again after 2 years - work, kids and life in general. :)

 

 

[TonyGee]

did you replace the O rings on the valve seats ? 

[sk1200]

10 minutes ago, TonyGee said:

did you replace the O rings on the valve seats ? 

Yup, and on the floats themselves so that they seat properly. Just installed the floats, seats and needles on an old (junk) set of B12 carbs, those are holding fuel fine with the same items. :O

[Dezza]

From where does the fuel leak flow? What 2 airholes? If you only get a leak when the float bowl is attached, then this may be where your problem lies. A sealing problem carb body to float bowl or a hairline crack. I assume you have removed carbs and the problem bowl, and then suspended the carbs whilst attached to a remote fuel supply. You can then manually operate the float to check if the valve shuts off the fuel supply as it should. Also, have you set the float heights?

[Captain Chaos]

he tried that already @Dezza

5 hours ago, sk1200 said:

When I drop the bowl, let fuel in and close the float with my finger lightly, no leak

 

[Wagola]

Float being restricted in cutting the flow of petrol off when the bowl is in place ? Maybe the float is catching on the bowl somehow ? 

[Upshotknothole]

2 hours ago, Wagola said:

Float being restricted in cutting the flow of petrol off when the bowl is in place ? Maybe the float is catching on the bowl somehow ? 

What they said. Try swapping the bowls between carbs 3 and 4?

[sk1200]

Tried swapping, tried the right hand bowls from the other carb set, no luck. Since the same hardware works in the other set, I keep thinking there is a crack in the 3rd carb body somewhere, only thing that comes to mind at this point. Thanks for all the responses so far!

[Upshotknothole]

11 minutes ago, sk1200 said:

Tried swapping, tried the right hand bowls from the other carb set, no luck. Since the same hardware works in the other set, I keep thinking there is a crack in the 3rd carb body somewhere, only thing that comes to mind at this point. Thanks for all the responses so far!

But it seals if you manually push the float closed? I was thinking maybe a leak around the valve seat, but that wouldn’t explain it not leaking when manually closed. Everything lines up ok? Nothing binding on that carb when everything is assembled? How bad of shape is the spare set? 

[sk1200]

16 minutes ago, Upshotknothole said:

But it seals if you manually push the float closed? I was thinking maybe a leak around the valve seat, but that wouldn’t explain it not leaking when manually closed. Everything lines up ok? Nothing binding on that carb when everything is assembled? How bad of shape is the spare set? 

Yeah, seals when I push it. Honestly it does not look or feel any different relative to other carbs when I set the floats.

 

I had to drill out pilot jets on no. 1 and 4 carbs of the spare set as the prior owner tightened them and broke off the heads, it sort of worked when I tapped out the remaining brass, but the thread is pretty weak. I guess I could split both sets and make a working one from them.

[Upshotknothole]

Tried tapping it with a mallet when it’s fully assembled and leaking? When all else fails, hit it with a hammer, and sometimes that will knock the float loose if it’s hung up on something.

[sk1200]

20 hours ago, Upshotknothole said:

Tried tapping it with a mallet when it’s fully assembled and leaking? When all else fails, hit it with a hammer, and sometimes that will knock the float loose if it’s hung up on something.

Yeah, that was one of the first things I tried. 

[sk1200]

Okay so I was not able to determine for sure what was wrong with the no. 3 carb, but I managed to make a working set of carbs from the two I had. After fiddling with the synchronizer for an hour, my bike is up and running again! Thanks for all your inputs!

[DAZ]

7 hours ago, sk1200 said:

Okay so I was not able to determine for sure what was wrong with the no. 3 carb, but I managed to make a working set of carbs from the two I had. After fiddling with the synchronizer for an hour, my bike is up and running again! Thanks for all your inputs!

Thanks for coming back and telling us that you sorted it out