Severe Fuel Leak From Exhaust

Fired up the KZ440 I bought off CL. I was planning on putting around the neighborhood, but immediately noticed a leak upon starting. The video provides an idea of what's happening (fuel being spattered until ignition is killed, at which point it just streams). Stops after a while, but proceeds in the same manner whenever bike is fired up. I traced the leak to a pinhole on the LH exhaust. Here is where I'm a little confused: the RH exhaust has an identical hole (I'll get some pictures up tomorrow when it's light out), so I'm guessing either a component is missing or they serve some sort of function. I'm a complete rookie, but it doesn't seem like fuel should even be in the vicinity of the exhaust while still in liquid form... Is this a correct assumption? What is the cause? What might the remedy be? Any advice would be much appreciated. Hoping this isn't too detrimental - really hoping to get on the road soon! Thanks in advance!

www.dropbox.com/s/v31d8xhz47jut9c/VID_20170419_192829.mp4?dl=0

If fuel is getting dumped into the exhaust system, then it's also getting into the engine oil, so you'll need to change the oil. The raw fuel may be that one cylinder isn't firing. When the engine is cold, you could start the bike & immediately start patting the exhaust header pipes to see if they are warming up. Don't get burned. One of them is probably cold, on the side where the fuel is leaking. Or to avoid getting burned, warm up the bike & spray-mist water onto the pipes to see if it sizzles.

The little holes in the mufflers are probably drain holes for the condensation to help minimize rust/corrosion of the exhaust system.

Is the stock airbox installed?

Most likely gunked up carburetors that are not stopping the flow of fuel when they get full, and probably a gunked up fuel tap on the bottom of the fuel tank. These are very common maladies on old bikes that have been unused for some time.
Carefully cleaning them and replacing the old rubber bits usually takes care of it.
As Martin said, there is very likely fuel in the crankcase. Be careful when you drain it. A little spark could have unfortunate consequences.

Either the petcock is leaking or set to prime. A float valve is not holding back the gas either.

The drain holes in the exhaust pipes often plug up from rust flakes. It could well be though that you only have one leaking float valve, not two.

Probably a piece of crud stuck at the needle and seat of the LS carb. Turn the petcock to prime (not running) and you should see fuel overflow at the carb to confirm. If not, clamp off the vacuum line to the petcock and run it in the prime position. If that's the fix, it's a cracked diaphragm in the petcock.

Does the vacuum line at the petcock go to the left or right carb? If it goes to the right, that's not the problem.

Im going through a similar problem at the minute,only the fuel is pouring out of the No.4 carb and not (yet) reaching the exhaust.Though I would be very surprised if unburnt fuel hasnt gotten into the cylinder. I disconnected the the tank and the fuel poured straight out,with the petcock in any of the 3 positions.
I have bought a rebuild kit and plan to fit that after giving the petcock a good refresh. I think I better check the oil also,just to be safe. The fuel I drained from the tank looks clean and the petcock filter also looks clean.

Keep in mind that fuel pouring out of the carb indicates in addition to the petcock problem there is also a problem with the carb, because the float valve in the carb should stop the fuel flow regardless of the petcock problem. If it doesn't the float valve isn't working (probably just dirty), or the fuel level is set too high, of the overflow tube is cracked. Ed

Yeah,I figured that.If its flowing out the back of the carb or into the exhaust,the float should be stopping it. (On my bike,the other (3) carbs are fine. I set the float heights,cleaned the carbs and everythings been rejetted, balanced and run on the dyno.There are no overflow pipes (BS34s). I even cleaned the offending carb again.)
My way of looking at it is to start at the beginning,which is the tank.If thats dirty,theres no point cleaning out the carbs or the petcock as theyll just get buggered up again. Is your tank clean Edward?
Then look at the petcock. Do you have a vacuum tap or the other sort? Is the tank filter clean? Im busy rebuilding mine. Scirocco dug up this link for me.Its very useful for rebuilding vacuum taps;
xjbikes.com/forums/threads/rebuilding-th...-valve-w-pics.25058/
(After that,Ill clean my leaky carb again and have a closer look at the float mechanism)
If you do get the tank and the tap clean,it might be worth putting an inline filter twixt tap and carbs.Just to be sure.

My tank is clean with zero rust. However, I still use an inline fuel filter just in case any muck is in the gas when I fill up. I figure the little screens on the petcock will more or less prevent the petcock from getting too dirty, but if they fail for some reason, or if tiny stuff passes through them the inline filter will prevent the carbs from getting contaminated. My bike came with a manual petcock; Kawasaki started using the vacuum operated ones the year after my bike was made. Ed

Okay, so here's where I'm at with all of the information provided (thanks to all of y'all, by the way!):

I will run the preliminary tests suggested by Martin and VTEC, then proceed with the steps David laid out (actual disassembly, cleaning, and replacement of tank, petcock, tank filter, carburetor, etc. components).

Does this sound like a reasonable approach to everyone? I appreciate all of the help! Getting these rookie hands dirty should be interesting!

The purpose of the drain holes in the muffler is to allow moisture to drain. Are you sure you are getting fuel and not water? Did you smell it to confirm?

If you are getting raw fuel out of your muffler drain hole, I would not attempt to start the bike until the leak is fixed. Getting raw fuel out of an exhaust pipe would mean fuel is also getting into the cylinder. Gas doesn't compress like air so there is a chance of bending a rod. Pull the plugs before turning the engine over to confirm no fuel in a cylinder.

Z1Driver wrote: The purpose of the drain holes in the muffler is to allow moisture to drain. Are you sure you are getting fuel and not water? Did you smell it to confirm?

If you are getting raw fuel out of your muffler drain hole, I would not attempt to start the bike until the leak is fixed. Getting raw fuel out of an exhaust pipe would mean fuel is also getting into the cylinder. Gas doesn't compress like air so there is a chance of bending a rod. Pull the plugs before turning the engine over to confirm no fuel in a cylinder.

Certain it's fuel. It wreaks of gasoline. So just be sure EVERYTHING is drained prior to starting work - is that what you're saying? Thanks for the feedback!