Nice! This was filled with a lot of good information and ... sarcasm!

 

In retrospect it is a bit snarky... sorry about that

 

It's all good in the neighborhood!

 

BikeBandit and most places can order this part for you and it comes in the normal catalog too. The main assembly is not a part that breaks easily hence why it's not sold, it's the "cover set" (that's the name for the part you need to replace) on the side that has the diaphragm and does break or comes loose inside. Usually if it comes loose inside it's likely to fail soon anyways and it might stop delivering fuel in the middle of nowhere this time so if it starts messin up, just replace it or get an AMA membership so you've got free motorcycle towing.

The leaking is typically from sitting for a long time where fuel dries up completely after the rubber has been worn in or when things get wet with fuel for say one ride then it sits for few weeks n you go back n forth like that. New or old rubber, doing this will likely lead to your o-rings on your carbs going bad, the bad petcock diaphragm, and it the most common cause for fuel to spill above the engine.

If you've got petcock issues from sitting, you very well might need a carb sync and jet cleaning at this point so you might just wanna buy the $15 in o-rings for the carbs and do the job all at once. Reminder tho, even with brand new fresh rubber, if you plan to let your bike sit then drain the fuel from the float bowls and maybe disconnect the main fuel line to let it drain out and connect it back (cuz you'll forget it if you leave it). Even doing this, if you frequently let your bike sit with a ride here n there, you will have these issues with the o-rings and diaphragm several times while you own the bike.

To replace you just remove the rear panels and maybe the front if you have big hands. You then unscrew the cover set (square x-men mini piece of toast screwed to the petcock valve) from the main assembly and swap in the new one. Replacing the cover set for about $40 with shipping will take care of it.

1992 Honda CBR600F2 Parts, 1992 Honda CBR600F2 OEM Parts - BikeBandit.com

Bike Bandit Part# 1649093

 

Excerpt from the How To I just wrote up about the petcock/cover set since mine failed again.

What goes wrong?
So when this plastic disc pops off, the diaphragm itself usually is worn. If you look closely at the nipple the plastic disc connects to you may see some wire mesh. What will be more apparent is the distortion of the diaphragm. Without a new one it's hard to compare against but if it's shot then it cannot sit flat in the cover brim. It will look distorted/warped when you set it in there especially with the plastic disc connected.

HOW DO I KEEP THIS FROM HAPPENING AGAIN!?!?!?!?!
As I understand the suction only occurs while the petcock is in normal operation which is when the petcock uses engine vacuum to force deliver fuel. You then go to reserve (which is like 1/3 your tank) and all still continues to operate just fine especially because you have float bowls in the carbs and fuel in the lines which acts as a small reserve as is... The ONLY difference that I know of here is that fuel is no longer forcefully delivered via engine vacuum, only gravity and with plenty of space to fill there's usually plenty of fuel available.
So my theory which I will test out will be to leave it on Reserve forever! I can't imagine this being an issue except while at the track and I accidentally ran the track the whole time last time on reserve with no issues. So I think this will be ok. If theory is correct, the diaphragm will never undergo stress causing the disc to become disconnected which is what blocks the fuel, otherwise reserve would also work. So the diphragm should never fail, and barring me being a bad *** motoGP racer (I'm not) I think fuel delivery will always be ok.