Well, I can't say 100% for sure, as I would have to look at the carbs myself, but let's forget about main jet sizing, and jet needle position, as I'm leaning toward float issues, since we've got fuel leakage.

There's not much to the floats - if everything is clean, they should operate just fine - it's rare that these type of floats need to be replaced.

If they are squeaky clean, and move freely - not sticking - but you still have fuel overflow, then as gpfan1 mentioned, you should check the float needle seats, to make sure they have a conical shape with NO concave at all, and no grooves... these items would indicate they are very worn, and the lack of seal would cause fuel to keep flowing in after the bowls are full.

An OEM F2 vacuum operated petcock eliminates the possibility of fuel flow "overpowering" the floats, but a gravity one will be fine, so long as you verify which position is "Off", and be certain to turn it off when you're not riding.

The F2 does not employ a fuel pump, nor does it need one.

 

Here's a picture from the manual showing carb and tank breathers and smog for CA bikes. All of the floats need to move freely. check the metal hinge pins for corrosion and gunk. I had several of my floats go bad after storing my carbs for 7 years. They sagged under their own weight and wouldn't seal against new needles I also installed. Once I put new ones in with new needles, no problems.

 

gpfan1 and JNSRacing

Thanx guys, you've been great help and deifinitely have widened my understanding of the bike. It might not be very useful in general but I feel way more confident with it once I know what's in there and understand how it works. I think every owner should understand up to some level his bike.

I can happily announce you that the other mechanic fixed in 2 days. Changed air filter, plugs, put a fuel filter on the tank, clean carbs, and fix the needles as they were put together totally incorrectly by the previous guy and generally that was the reason engine got so much fuel in it.

Bike works fine, doesn't stall. It is a bit bobbly on lower revs sometimes, feels like carbs need to be timed a bit, but pulss fine both in low and high revvs , no dips in power. Generally i'm pretty happy. Lets hope it holds up!

Thank you.

 

That's good to hear!