petrol leaking from breather pipes. - SV650.org

13-03-06, 08:33 PM

i've got a problem with my bike... which is quickly tunring into a bit of a lemon.

i had petrol coming out of the breather pipe that runs down the rhs of the engine towards the back, nearish the brake lever. This started a couple of months ago, so i did a bit of a bodge

and i popped a bolt into the rubber pipe. Since then the bike has ran fine, so I thought nothing more of it.

more recently, the bike has had a bit of a misfire and i got to work stinking of petrol. On investigation, theres a small white plastic pipe to the right of the air filrer box next to the frame. (open topped, looks like the top of a 2lt coke bottle) that has petrol spilling out of it... its full to the brim with petrol and it keeps oozing over the top.

i've no idea why petrol is coming out of my breather in the first instance or what this new pipe is that it now leaking...

any ideas. thanks for your help

karl

13-03-06, 08:42 PM

breather pipe is to let petrol out as its an overflow from the tank(should be an hole near where the filler is..this catches the excess and drains out..UNBLOCK IT!!!! the white plastic thing could be a fuel filter..maybe shouldn't be opened top?!?..to stop crud..and will be full of petrol.

any chance of pics?

if its coming out of the breather pipe..are you spashing the filler with petrol??

13-03-06, 08:53 PM

maybe breather pipe isnt the right word... its a black rubber pipe abput 8mm dia that runs vertically from the tank down behind the crank case and stops just behind the back brake pedal.

i'll try and get some pics tomorrow of the white open topped pipe next to the air box tomorrow. and see if the breather next to the filler cap is blocked..

other than that i might try and fix it with a box of matches..

k

embee · 13-03-06, 08:57 PM

Could be that your filler recess drain pipe is rusted through inside the tank and is letting fuel out that way. How old is the bike?

If it is rusted through it's rather bad news. I'm not aware of a successful way of repairing these, replacement tank required.

Not sure what this "coke bottle top" thing is that you're describing?

14-03-06, 08:10 AM

ok maybe fixed it. looked again this mornring and a rubber grommit had come off the top of the pipe next to the air box... and it was marked LCC. still no idea what it does. so i popped that back on and its stopped the petrol leaking out... question, should there have been petrol in there in the first place. it look awfully like a coolant pipe

and the leak out of the bottom overflow pipe. well i've popped my little bolt back in it. i think you might be right about a hole in the overflow pipe in side the tank. it was in the garage a few months ago with sh!te in the carbs, and they cleaned the tank. probably a hand full of nuts and bolts and rattled around for 10 mins, and possibly holed the overflow pipe. so the bolt can stay in the pipe for now.

karl

14-03-06, 08:19 AM

It think there are usually two pipes to the petrol tank.

An air breather pipe to let air in and prevent a full vaccum from forming. This would stop petrol leaving the tank.

A drainage/overflow pipe which lets any water that get past the cap to the internal rim plus any spilt petrol drain from the tank.

Try blowing air up from the end and you'll find its final location and get an idea of its purpose

13-03-06, 08:33 PM	#1
kjames Guest Posts: n/a	petrol leaking from breather pipes. i've got a problem with my bike... which is quickly tunring into a bit of a lemon. i had petrol coming out of the breather pipe that runs down the rhs of the engine towards the back, nearish the brake lever. This started a couple of months ago, so i did a bit of a bodge and i popped a bolt into the rubber pipe. Since then the bike has ran fine, so I thought nothing more of it. more recently, the bike has had a bit of a misfire and i got to work stinking of petrol. On investigation, theres a small white plastic pipe to the right of the air filrer box next to the frame. (open topped, looks like the top of a 2lt coke bottle) that has petrol spilling out of it... its full to the brim with petrol and it keeps oozing over the top. i've no idea why petrol is coming out of my breather in the first instance or what this new pipe is that it now leaking... any ideas. thanks for your help karl

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13-03-06, 08:42 PM	#2
zx6man Guest Posts: n/a	breather pipe is to let petrol out as its an overflow from the tank(should be an hole near where the filler is..this catches the excess and drains out..UNBLOCK IT!!!! the white plastic thing could be a fuel filter..maybe shouldn't be opened top?!?..to stop crud..and will be full of petrol. any chance of pics? if its coming out of the breather pipe..are you spashing the filler with petrol??

13-03-06, 08:53 PM	#3
kjames Guest Posts: n/a	maybe breather pipe isnt the right word... its a black rubber pipe abput 8mm dia that runs vertically from the tank down behind the crank case and stops just behind the back brake pedal. i'll try and get some pics tomorrow of the white open topped pipe next to the air box tomorrow. and see if the breather next to the filler cap is blocked.. other than that i might try and fix it with a box of matches.. k

13-03-06, 08:57 PM	#4
embee Member Mega Poster Join Date: Jul 2003 Location: Warwickshire Posts: 2,802	Could be that your filler recess drain pipe is rusted through inside the tank and is letting fuel out that way. How old is the bike? If it is rusted through it's rather bad news. I'm not aware of a successful way of repairing these, replacement tank required. Not sure what this "coke bottle top" thing is that you're describing?

14-03-06, 08:10 AM	#5
kjames Guest Posts: n/a	ok maybe fixed it. looked again this mornring and a rubber grommit had come off the top of the pipe next to the air box... and it was marked LCC. still no idea what it does. so i popped that back on and its stopped the petrol leaking out... question, should there have been petrol in there in the first place. it look awfully like a coolant pipe and the leak out of the bottom overflow pipe. well i've popped my little bolt back in it. i think you might be right about a hole in the overflow pipe in side the tank. it was in the garage a few months ago with sh!te in the carbs, and they cleaned the tank. probably a hand full of nuts and bolts and rattled around for 10 mins, and possibly holed the overflow pipe. so the bolt can stay in the pipe for now. karl

14-03-06, 08:19 AM	#6
mysteryjimbo Guest Posts: n/a	It think there are usually two pipes to the petrol tank. An air breather pipe to let air in and prevent a full vaccum from forming. This would stop petrol leaving the tank. A drainage/overflow pipe which lets any water that get past the cap to the internal rim plus any spilt petrol drain from the tank. Try blowing air up from the end and you'll find its final location and get an idea of its purpose