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Gas leaking from carb overflow tube....

36K views 115 replies 59 participants last post by  Logan r 
#1 ·
Stock carb.
Will this effect performance?
I have an inline shut-off valve installed so I can turn off the gas without using the petcock.
Looks like it's only leaking when I shut the bike off.
What usually causes this?
What's the fix or fixes??

Thanks
 
#2 ·
When the valve is shut-off or bike shut-off?

Could be as simple as a slightly high float level. I have no shut-off valve but when I had a bad bowl gasket the carb would leak when the bike was shut off. Lowered the float slightly and cut a new carb bowl gasket. Now it is dry.

If just when the bike is shut-off then the fuel valve is shut-off (long-shot) maybe the ambient temperature or heat from exhaust/motor is causing the trapped gas in the line to expand and be forced into the bowl out the overflow.

Of course (you know) if it is always (bike on or off) something is holding the float needle open and it needs to be cleaned
 
#3 ·
caferacer said:
Stock carb.
Will this effect performance?
I have an inline shut-off valve installed so I can turn off the gas without using the petcock.
Looks like it's only leaking when I shut the bike off.
What usually causes this?
What's the fix or fixes??

Usually it is only the float sticking. Somehow alot of them come this way or shortly after owning them this happens. It could be anything from plastic from the gas tank molds to material from the shutoff valve or just plain old dirt. Take the bowl off the bottom of the carb and clean it out with carb cleaner the blow out the fuel inlet on the carb to see if it comes out the bottom (needle seat).CAUTION WEAR SAFETY GLASSES carb cleaner burns the eyes. Use air if at all possible. Hope this helps ,Troy
 
#6 ·
For what it's worth..... we had the same problem with a few of our bikes and were advised to simply pick the back of the bike up about 8-10" and drop it... repeat this about 6 times. BINGO... worked and never leaked again. Leading us to believe what was mentioned in this thread... small particles of whatever stick the float pin... the dropping of the bike ( just the rear lifted ) free'd up any dirt etc

As also mentioned.... if you haven't replaced the stock fuel filter ( ie - cheap China Junk that is very brittle and houses a magnetic ball in most cases to supposively draw metal particles out of the fuel which is good in theory however draws even more heat from the muffler/head/motor which will liquify that garbage stock filter and choke off fuel flow...) replace with auto parts store filter.

We give all our customers KIMPEX fuel filters to replace the junk stock filters. $4.00 is well worth the frustration and disatisfied customers.

Hope this helps
 
#7 ·
Thanks 2KOOL.
I do have an aftermarket filter installed and will also try the tip you sugessted.

guy on the couch I noticed you stated you found one.
Just wanted to let other members know that I got the shut-off valve from a local small engine shop for 6.00 ea.
 
#8 ·
fuel leak

everytime i turn my bike off and let it sit the fuel starts to shoot out the overflow hose until the tank is empty..i took it aprt cleaned it, checked the float valve and everything, put it back together, ran it and put it on the stand , the next morning all the fuel was out again.. any suggestions??
 
#10 ·
yeah i had the same problem, make sure the needle rod thing is connected to U propley(in the float chamber), also try starting it with the fuel off. There should be enough fuel in the float chamber for it to idle for like 30 seconds (only if its full), then turn the fuel on and let it idle for another 30 seconds. But if the rod needle thing isnt connected properly it just wont work. In fact mine leaked so much i didnt bother riding it.:mad: because if that rod thing (gotta learn my carb parts:D ) theres nothing stopping fuel from coming into the float chamber.
 
#13 · (Edited)
%%%HELP%%%overflow.. very leaky????

high there, so i have this problem with my carb its a leaky one
you know that overflow thing well when i open the lever to let the engine suck in gas most of it comest out the ottom of the carb from the line that gos to nothing.

a full tank of gas can be gone in 10-15 minutes

any help would be apprechiated
 
#14 ·
so gas is flowing out of the over flow tube? if soo take off the bowl off the carb u will still a bronze lookin fork thingy there bend the arms a little not a lot very little, downward then put everything back together

was the lever u were refering to the choke lever? u dont need the choke lever pull it down
 
#15 ·
carb overflow

I am having a problem with my over flow. When i run the bike, it piss's all over the place. I took the floatbowl off to see if the float was stuck, nope. I uncrewed the pin in the needle a little. Hooked up the fuel line to see if it would shut the fuel off and it did. Well......it is still leaking out the over flow line !! Any body have this problem??

The next step is to bend the arms a little more down to make sure the float is shutting off the fuel. Just wanted to check to see if anybody else had this problem.

DK
 
#24 ·
Re: Bike leaks fom overflow

raise up the bikes back tire like 12-15 inches off the ground and shake it up and down. the float is stuck.
 
#25 ·
Re: Bike leaks fom overflow

if that doesnt work you are going to have to take the float bowl off and make sure that the little needle attached to the float arms isnt stuck and if thats not the problem you might have to bend the arms up a bit
 
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