Thread: carb keeps dumping fuel out of the bowl overflow

Hi there

I've got a lifan 110 with the included carb in my ct70 frame. Using one of the Dr. ATV universal petcocks with two inputs, and filter.

Twice in the past week I've gone into the garage to find that the bike has puked up all it's fuel overnight. The last time I at least had a pail under it.

After it happened once, I tweaked the float a bit and eyeballing it looked like it was set low enough. If I adjust the float too much, will the bike not run at all, or still run long enough for me to get far away from home and tools?

The most irritating part is that both times the petcock was on the OFF position, but it still drained the tank. I took careful note this last time, it was maybe 5-10º away from the off position, so maybe I just need to be more careful with that. I think I may also just get into the habit of putting on a medical type scissor clamp on the hose between the petcock and carb every time I park.

thanks for any advice!

Hi Chris, I would get rid of the aftermarket carb. It will probably give you other headacks sometime down the road. You can get a good mikuni off ebay for real cheap (plug & play) But if you keep your carb you can always turn you gas cap valve to OFF position when you park. If the carb leaks it will stop once it runs out of ait and limit the damage. I am not sure why it leaks in the first place. I am sure you will get some more feedback on the forum to help solve the problem.
Best of luck.
Harry

I`m not sure with your carb, but one of my bikes (K1) does it with the stock carb. It leaks out of the drain hose. My assumption is this: The float needle doesn`t seat correctly and neither does the drain valve seat properly. Now, I have a snow blower that leaked fuel even after I rebuilt it. Turns out that there was a little tiny air vent hole in the side that if pugged, would cause the bowl to overflow and thus drain. I stuck a wire in it and it stopped draining fuel.
On the CT70, I tried to put a wire through the side air vent (the long circular pipe off the right side of stock carb), but I`m not sure if I unplugged it or not. I`ll have to wait to pull the carb apart again.

Just a thought!

Ian

sounds like a sticky float

On my last project the stock carb was leaking gas from the drain tube.Tried everything,float,etc...including changing the drain screw with one i knew was good.Ended up putting a new bottom on and that solved the problem.The only thing we could figure out is that maybe the stand pipe had a pin hole in it somewhere.Hope this may help.

you have to get the float adjustment real close on those carbs.. the float is circular correct?! and the brass overflow tube sticks up through the middle of the circular float correct?.. well the float will get hung up on that brass tube very easily. when you go to put the carb on the motor gently shake it and make sure you can hear the float rattling up and down! i had the same problem with the same carb from dratv just last week!

those ideas all sound good, I'll check to be sure the float isn't sticking on the tube. I don't believe there is any holes in the overflow tube, as I filled it up with water and it didn't leak at all. If only one could see what was happening INSIDE the bowl while it was still closed...

And failing that, I'll just employ a clamp on the petcock to carb fuel line when parked.

I'll update when I get some new info, thanks everyone!

Trail 70's like to leak out the overflow tube due to the kick stand being bent or worn. Check it!

Later Kevin

Good point.But that wasn't the case with mine.

They also have "in line" petcocks. Cut your fuel line in two (yes...), plug this in and you can shut it on and off for fuel flow.

Something like this:

INLINE FUEL SHUT OFF 1/4" BARBS SOLD EACH (88C)