Topic: Heavy Fuel leak

[MrBaklava]

Hey there,

I recently discovered a heavy fuel leak on my CB550k.

I initially thought it was a stuck float, so pulled the bowl off the carbs and everything looks clean and free moving.
After putting the carbs back on, the bike fired up and the revs felt more responsive than before - it was obviously happy to have the carb cleaned.

Then I finally spotted the location of the heavy fuel leak - it's coming from the location pictured, just at the bottom of the airbox, a little pipe that leads to nowhere.

Can someone please tell me what this pipe/tube is for, a fuel return maybe? There's no obvious pipe that's disconnected.

Thanks in advance for your help.

[Bodi]

One of the carbs is apparently leaking, with its overflow tube blocked.
Fuel level rises with a leaky float valve and drains out the lowest place it can. If the bowl overflow is blocked that's either into the intake or back to the airbox, or both.
Hopefully your cleaning has fixed that, but if fuel is still dripping from the airbox drain then nope.
The drain should, I think, have a tube down to under the engine with a fishmouth end. It's to let any water that gets in dribble out. Without a tube, the opening is really small and the bit of unfiltered air that gets in isn't serious.
If it still dribbles fuel, fix the leaking carb. Make sure all the carb overflow drains are open. If you have drain tubes connected to the nipples, maybe those are blocked. Tubes are a good idea as dripping fuel on a hot engine is not excellent practice, but they can get plugged with dirt or (usually) with insect detritus. Check  engine oil level and take a whiff of it - it may be diluted with gasoline or be contaminated by it and it should not smell of gasoline at all. At riding temp gasoline in the oil evaporates off, but the additives remain and should not be in engine oil.

[Shtonecb500]

u have a stuck carb and its overflowing into the airbox.

[MrBaklava]

Thank you for the replies.

I found one of the drain tubes from a carb bowl was crimped in the stand. I've unblocked it but didn't get the chance to start the bike again.

Simply unblocking this tube won't fix it right? it'll just mean than instead of pushing fuel back through the airbox, that it'll drain from the drain tube Meaning it's a float issue after all.

Is there any way to adjust the floats on the bike? It was a pain in the ass pulling the carbs off past the rubbers.

[newday777]

Thank you for the replies.

Is there any way to adjust the floats on the bike? It was a pain in the ass pulling the carbs off past the rubbers.

No. The carbs have to be off and tilted so the floats just close the valves to adjust them properly.

Use a heat gun to soften the boots to get the carbs off and on easier.
Did you remove the air cleaner box first?