Topic: 550 K1 leaking gas from overflow tubes of carbs

[Bob550four]

Ok, I have no idea how to fix this issue with my carbs, when you've got any amount of fuel in the tank and the petcock on, the carbs will pour fuel out the overflow tubes.   

what I'd like to understand is WHY do they do this?  my needle/seats are good I think, but it sounds like it runs rich all the time.  could my floats be off or am I just needing a rebuild kit? 

when I got the bike, I synched the carbs, adjusted the fuel mix screws to 2 turns out, and cleaned the carbs so well you could eat from them.

anyone got some help?

[TwoTired]

Inside the float bowl is a stand pipe that can acquire a crack.

Float height can be set too high, resulting in an actual overflow.

Dirty fuel can have chunks in it that prevent full closure of the needle/seat.

The floats may not pivot freely.

Needle and seat may be damaged preventing effective fuel shut-off.

Needle seat oring compromised.

Does this occur while parked on side stand, centerstand, or both?

Cheers,

[Bob550four]

it occurs alll the time, even when the bike is running.

[AOD]

Does your petcock shut off?  Mine leaked and would overflow the bowls when it sat, even in the off position.

~Adam

[Gordon]

Does your petcock shut off?  Mine leaked and would overflow the bowls when it sat, even in the off position.

~Adam

A petcock that doesn't shut off completely can only contribute to carb overflowing if one of the things that TwoTired listed is happening at the same time.  With everything in the carbs working properly, you can leave the petcock in the "on" position with no leaks resulting. 

[mattcb350f]

Inside the float bowl is a stand pipe that can acquire a crack.

Float height can be set too high, resulting in an actual overflow.

Dirty fuel can have chunks in it that prevent full closure of the needle/seat.

The floats may not pivot freely.

Needle and seat may be damaged preventing effective fuel shut-off.

Needle seat oring compromised.

Does this occur while parked on side stand, centerstand, or both?

Cheers,

+1, That pretty much covers it 

Does the 550 have individual overflow tubes for all four carbs like the 350? If so, take a close look at which ones are venting fuel. You may find it's only one or two carbs spilling all the fuel 

 Matt.

[Bob550four]

I"ve found that its usually all of my carbs, or 3/4 of them depending on the day.  right now, I think my floats are the problem, likely too high, and I dont doubt it either.

[squirley]

I just took my carbs out for some cleaning, put them back in and bwammy! 3 out of 4 were spewing consantly.  Took them out, opened the bowls and polished the float rods, and bwammy, they all work great.  Just a little elbow grease on the float rod can keep them from sticking.

[goon 1492]

don't forget that the floats can go bad too leaving the bowl constantly filling up, i usually tested it in some gas in a cup to make sure it still floated and didn't sink , i used to set my floats on my old honda elsinore too keep the bowl alittle over full but that was because i usually had that thing at a 45 degree or steeper climbing a hill and didn't want the carb to empty the bowl while i was gettin with it.

[TwoTired]

don't forget that the floats can go bad too leaving the bowl constantly filling up, i usually tested it in some gas in a cup to make sure it still floated and didn't sink , i used to set my floats on my old honda elsinore too keep the bowl alittle over full but that was because i usually had that thing at a 45 degree or steeper climbing a hill and didn't want the carb to empty the bowl while i was gettin with it.

All the 550 carbs I have seen used composite floats.  I've seen other carbs with brass floats develop holes and sink.  But, I've not seen a composite float fail to float.  How does the material change to prevent floatation?

[Hope]

+1, That pretty much covers it 

Does the 550 have individual overflow tubes for all four carbs like the 350? If so, take a close look at which ones are venting fuel. You may find it's only one or two carbs spilling all the fuel 

 Matt.

No, there are 2 overflow tubes.... not 4

[TwoTired]

+1, That pretty much covers it 

Does the 550 have individual overflow tubes for all four carbs like the 350? If so, take a close look at which ones are venting fuel. You may find it's only one or two carbs spilling all the fuel 

 Matt.

No, there are 2 overflow tubes.... not 4

All the stock CB550s have 4 over flow tubes, one for each carb attached to the carb bowls.  There are, however, two VENT tubes, if you don't count the carb interconnect couplers.

Cheers,