Fuel Leak

[Rangrally]

Hi all,


My 98 FZS started to leak fuel about a month ago, I stripped off the tank and carbs and found a tiny split in the (now brittle) pipe to the carbs so I replaced all of the original pipes with good quality fuel hose. This cured the problem for a few weeks but I now have the same problem occurring again    SO today I took it all apart again and took the carbs apart to look for potential problems but everything looked ok so I put it back together and went for a run: no leaks on the run but it did have a period of spluttering which cleared. I thought I had solved the issue so put the bike away, however,  checking it an hour or so later the bottom of the float chambers are dripping petrol and it now seems the fuel pump has given up the ghost as it has stopped ticking........I hope this is a coincidence and it is something I have dislodged which is stopping it running (will be checking this tomorrow)


So the main question is: has anyone experienced leaky carbs and what was the cure? Could the float levels be wrong? All the bowls seem in tact and close correctly.......help!

[bikemad62]

Maybe you have a leaky/ stuck float valve. Give the carbs a gentle tap with a mallet. Mind the tps its plastic and breaks easily.
 

[virtual bodysnatcher]

Sounds like float valves to me too, my RG500 did it a lot, the rubber bit on the float valve sticks it to the jet just enough to stop the float rising fully and lets fuel through so's it dribbles out of the overflow, happens more if the carbs are drained as everything's dry, so could be the answer. a tap on the carbs is a good start or if not if you can take the floatbowls off (with fuel shut off) see how well the floats move up 'n' down and have as good a look at the valve seat, smallest speck of dirt will keep it open enough to leak, hold it shut and turn fuel on, see it it leaks, just lifting them up 'n' down a few times can fix it.


A little fuel can go a long way leaking!! Is unlikely all four'd be sticking tho'......


The drain screws are done up fully aren't they.....



Modern fuel's much more corrosive than old 4 star so gives rubber a hard time.


Fuel pump doesn't always make a noise if the pressure's adequate, or at least mine doesn't 

[Fazerider]

More than one carb dripping suggests the source of the leak may be higher than the float valves, perhaps a crack in the T-piece where the fuel enters the carbs or a faulty O-ring at one arm of the "T".
But are you certain it's coming from the carbs? If there was a leak from that area it's hard to tally that with the fuel pump not ticking. I'd check the pump itself isn't leaking, the fuel may be running along the outside of the hose or dripping onto the carbs making it appear as if the leak is lower than it really is.

[Rangrally]

Many thanks for the replies so far: The fuel pump is working now - I must have dislodged the connector whilst messing about with the carbs etc, waggled it and it now works fine.


I went for a run and found no leaks, came to rest and noticed a hissing from the tank so I checked the breathers and found one kinked  though that may have solved it but an hou or so later and the leak is back. I now think it is one (or more) of the float levels set wrong as it does seem to be seeping out of the joint between the carb body and bowl, but it is difficult to eliminate as the fuel seems to "track" all over the underside of the carbs/float bowl. Next step is to remove the carbs again and look at the float seatings and levels.


Once again many thanks for the help.