fuel leak?

duff_boy · Sep 5, 2008

Hey guys my bikes got a lifan 150 with standard carb its a mikuni, i assume the 26mm or whatever. Anyway, when its riden fuel drips out the drain tube from the bottom of the float bowl. Perhaps as much as a drop every 5 seconds.

I thought this was purely just a drain tube, you undo the screw to drain the fuel out of the carby. So i made sure the screw is nice and tight, even tried another screw from a differnt carby. No change.

Do this also work as some sort of overflow or something? Why is it doing this?

duff_boy · Sep 5, 2008

Oh btw, loving the lifan 150, no problems apart from this. Awesome little engine. Mountains of torque just off idle with a strong top-end to boot. Seems to go better than my mates bike with a ducar 200cc. Ive advanced the timing and de-baffled the pipe today, cant wait to take it out tomorrow and see how it goes. Just gotta make sure you give it a good kick otherwise the kickstart can kick back a lil if your lazy when the timing is advanced. lol i did it once and it hurt my foot(not to mention probably the kick start gears as well

) oh well wont do that again.

rumble · Sep 5, 2008

think you may find its not coming from the drain hole.
My bike leaks from the breather vent hose which is about half way up on the other side. You shold have two hoses coming off the carb. One a draind the other a breather.

duff_boy · Sep 5, 2008

Its definitely the drain that's dripping mate. I'm a mechanic(well a diesel fitter) but not so familiar with bikes/carbys etc. But still familar with most stuff and don't get confused lol.

Oh btw, it only does it when its running, i could leave it sitting all day and it doesnt leak at all.

Custom · Sep 5, 2008

its most likley the float level being just a touch to high, seen this problem a few times before. The drain tube also works as an overflow.

thump*140 · Sep 5, 2008

yeah what custom said... try setting the float a little lower... pretty easy, remove the float bowl cover/ carby base, and bend the float down GENTLY. this effectively makes the float needle seal earlier, with a lower level of fuel in the bowl. To lower the fuel level in the float bowl, bend the float down, to raise the fuel level, bend the float up. However, DO THIS GENTLY!!!