leaking fuel overflow
 

can anyone tell me why my fuel overflow tube leaks when i shut off my 94 xt600? i left it for about 6 hours and there was about 1/4 cup of fuel that had spill out into a bucket.

thanks in advance.

sorry can't help you there...
well I have the same problem on my KTM LC4 640 / 2002 with the 30Lt tank, and the matching vacuum pump even if all tabs are turned off carefully... I tried to adjust the needle valve and the float of the carb, even replaced the needle valve for a new one, but still no luck... loosing fuel while parked up...
On the other hand I'm not sure if it got some thing to do with the tilted carb regarding the side-stand only support...

spooky

Angelglo, when you say "bike shut off", do you mean fuel tap turned off - or is it a vacuum tap?

If its an "on/off" tap it should be turned off every time its parked up. If you are doing this, take the fuel pipe off the tap and turn it on, then off, and see if it stops the flow immediately. If not it needs a repair kit or replacing.

You 100% sure its out the overflow, and not weeping out the bowl and running down the overflow pipe?


This still ins't the reason fuels coming out of the overflow. This is due to the fuel needle valve leaking. Even if you replaced/cleaned it, there must be a slight weep due to wear/bad alignment or (best bet) dirt. Are you runnin g a fuel filter in the fuel pipe - if not probably worth it, them clean/check the needle again.

Good luck.

Perhaps your float bowl is sticking or incorrectly set up.

Set the float height as per book specification.

Old school method could be to tap the float chamber with something like a screwdriver and see if it stops. Not a permanent solution though.

SCEWRDRIVER, my arse - used to be a 3lb hammer, at the very least :blushing:

LOL... What were you riding ?? A sherman tank ?? :Beach:

thanks guys. i just took apart the carb, cleaned it, and put it back together. it is coming out of the overflow, no doubt. i do leave the fuel shut of in the on position when i partk it. ive always done this will all my motorcycles but i never had any problems with overflowing but again, this is my first dual purpose. i did not check the float level in the bowl because i didnt think there was a problem with this before it took it out. i guess i will pull it out and check it. but according to the manual, it looks like a pain in the but to do this.

Let's be clear:

1. You turn off the fuel tap on the tank when you park up
2. Fuel is leaking from the carb overflow pipe.

If those are correct, then you have two problems.

1. Your fuel tap isn't sealing properly
2. Your float valve is sticky or dirty.

If you've had the carbs off, you were 95% of the way to checking the floats. Carbs off, float bowls off, and check that the float valves are sealing properly. Test 1 - is the needle sticky in its bore? Test 2 - with gentle pressure on the needle, can you blow through the feed pipe? If the answers are Yes and Yes, then you have a faulty float valve.

Also - check the float's are sound - they can leak and fill with fuel which stops them "floating" so they don't shut the neddle valve. This is common on the old Amal carbs, like wot I got on me 1970 trumpet, not that Yamaha use them!!!!!

Hi all,

Sorry to resurrect an old thread but im having the same problem.

When i park the bike and leave the tank tap to on position my bike leaks petrol everywhere. I have checked the float, needle, seat, rebuilt the carb etc. still it leaks.
I have came to the conclusion that the head pressure in the tank causes the needle to unseat itself. This happens regardless of whether the bike is on the sidestand or vertical. Have also replaced the o ring between the carb chassis and bowl [ it is additional to the gasket and seats around the long brass pipe]

Any one have any tips on how they rectified this or did you just learn to live with a leaky old XT?

Cheers
Cdag

Have you replaced the float needle and seat ? Checking that they're clean doesn't mean that they're not worn.

Also check your float is 100% sealed. Hold it under water and check for tiny bubbles. Its very rare, but I once sore a float which wasn't airtight and fuel was seeping in. Obviously affecting its buyoncy.

Have you tried adjusting the tang on the float valve ? Tiny adjustments make a big difference.

If all else fails, replace the carb or turn the tap off and get on with life.

Sent from my G7-L01 using Tapatalk

I had the same problem. Turned out to be a combination of a leaking petcock (fixed just by taking it apart and cleaning it) and a float which I'd set to the wrong height.

Thanks for the replies,

Have replaced the needle seat and adjusted the float height to no avail. I may just try again next time i have it apart.

Petcock was dodgy but has been fixed.

Cheers
Cdag

Make sure you replace both the seat and the valve at the same time.
If thoose thigs are working, the only thing that will make it overfloat is the float beeing way out of adjustment.

Keep us updated =)

Also make sure the o-ring UNDER the seat half of the "needle and seat" is replaced with a new one ( Viton ideally for the ethanol in todays fuel). Many people rebuild a carb but don't take out the seat and change that o-ring which lets fuel leak right around the float needle . Very, very common on the DRZ but I've seen it lately on others as well .