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leaking gas from feeder tubes

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adam h

leaking gas from feeder tubes

Hi Everyone,
Quick question I was hoping to get some support with. I have a 72 CB750K. Currently when I start it up it begins peeing gas out of the feeder tubes. I'm guessing there is a block in the carbs but I wanted to see if there were other possibilities before I took them off and cleaned them. I just cleaned them this spring which is why I'm a bit perplexed they would be clogged.

Backstory (not sure is this is helpful info?): Cleaned the carbs last spring. Kind of did it halfway to avoid using really toxic cleaner. Used Pinesol, took all pieces apart and srubbed away. Poked through jets with wire Did not soak in carb cleaner. Put back on bike and started well. Took to a home mechanic who replaced ill fitting boots and checked to see if they needed tuning. They did not. Hasn't been ridden a ton but does have fuel stabilizer in tank. Perplexed that it would clog so soon?

Any other things it could be before I clean carbs again? Any suggestions much appreciated.

Adam

TOOLS1

Re: leaking gas from feeder tubes

Administrator

"Feeder tubes?"

If you are referring to the hoses coming from the bottom of the carbs, these are the overflow tubes. Gas is supposed to run out these tubes when the float bowels over fill. There are three things that can cause this. First is the float set too high allowing the fuel level to be too high. Second a dirty, or worn needle valve, and seat not sealing. You can use a Q-tip and chrome polish to clean them, and sometimes it will cure the problem. Last, you could have split overflow tubes in the float bowel. This happens when water gets into the carb, and then freezes.
TOOLS

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1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)

icerigger

Re: leaking gas from feeder tubes

In reply to this post by adam h

Yeah, what Tools said.

If you're talking about the cross tubes running between the individual carbs you're goint to have to break them apart and replace the o-rings. This happens a lot when old carbs are partially cleaned and you disturb the 40 year old seal and the o-ring is too brittle to reseal.

Livin' my life like a song.

1985 Honda Rebel 250 - "Birdie"
1979 CB750K - "Behemoth"

hambone

Re: leaking gas from feeder tubes

i just had this issue with a set from my 550.turned out my float was dropping so far down..the needle valve would get stuck going up because it wasnt straight! small tab on the side of the float that prevents this i overlooked on the rebuild.bent it to proper spec and problem fixed.just a thought

80 cb750f,80 cb 900c,80 cm 200,83 xlx,75 xlh