Newbie needs help

Hello all, I bought my first bike yesterday (xj750) and there's a line coming of the grey box connected to the carb that is leaking fuel. I don't know where it connects or if it's supposed to connect somewhere but I may be new but im pretty sure leaking fuel is bad lol

The line is on the bottom side of the box

 

Drain hole for air box, and gas coming out the bottom means one or more of the carburetors are overflowing. Odds are some fuel has gone the other way too and contaminated the oil so that will need to be addressed

Did you trailer it home or was it a runner - any history on the bike is always helpful

Odd are the carbs will need a clean and rebuild

And, I can't quite tell from the picture but if you still have the stock vacuum actuated petcock it is not meant to be left in the prime position

 

Would that cause run away on start up? She runs and fires up real quick but I trailered her home. One of those storage unit specials.

As for fuel in the oil do I just need to do an oil change? Sorry I don't know squat about bikes

 

What is the correct position? The guy just showed me how to on the gas and turn it off. That's it lol

 

If it is a vacuum operated petcock it will have a vacuum line attached to it that connects to one of the carburetor manifolds. The correct position for vacuum operated is "ON" until "RES" is needed as fuel should only flow in these positions when the engine is running and a vacuum is present. The prime position fuel flows without a vacuum and should only be needed if the bike has not run for a while and the carburetors are empty, or need "primed." They do go bad so they need to be tested occasionally

It the petcock has been replaced with a non vacuum type the correct position is "ON" or "RES" if needed when running, but should be set to "Off" when the bike is parked and not running. The vacuum line from the carburetor manifold should be capped like the other three.

Check the oil level on the sight glass to see if it is above the inscribed line on the crankcase cover. Remove the oil filler plug and take a whiff to see if it smells like gas. If gas is present in the oil do not run the bike until the oil is changed.

Normal startup with the enrichment lever (choke) set they tend to rev up to approximately 3000 RPM initially. Anything much higher is could be an indicator of a vacuum / air leak or just lack of maintenance / adjustments

And, as mentioned earlier odds are the carbs need serviced, and at the very least the overflowing has to be corrected before even thinking about starting it again as you would just risk contaminating the oil again.

Some educational reading:

https://www.xjbikes.com/forums/threads/the-information-overload-hour.27544/

https://www.xjbikes.com/forums/threads/in-the-church-of-clean.14692/