Welcome Aboard !

The reason for the fuel shut off (or "petcocks") is that the fuel tank is located ABOVE the carbs. Once is a great while, the force of the fuel (the weight and height of the fuel itself) exerts a greater pressure on the float valve than it can withstand. There may also be a small amount of trash on the valve's seat, which is assisting. When these stars align, fuel then flows into the intake, down past the inlet valve, past the rings and into the engine sump... where it dilutes the engine oil. This is all done by gravity, which having been discovered by Issac Newton in 1679, has been a fairly reliable and constant force since that time.

So, the 2 easiest ways to inspect for fuel in the sump and dilution of the engine oil are: 1) Look at the dipstick. Did the oil level magically increase ? 2) Take a big whiff with your nose down next to the open dipstick hole. Do you smell fuel ?

It's actually a fairly rare occurrence, but it is a REAL concern. When it does happen, you will be required to change your engine oil. (If you let the oil sit in an open container, there's a good chance the bad stuff may evaporate over time and the oil might be safe to use in your lawn mower. This is all based on the expense of the oil you use.)

• Most of the time, the first notice is that the engine immediately expels the excess liquid onto the shop floor within 10 seconds of starting. This is the equivalent of a human coughing up a huge clot of blood. Both make a mess and both should be taken seriously.

• Whether to change the engine oil filter or not depends upon whether the engine was run. If you discover it before starting, then there's no need.

4 hours is not a long time. I highly doubt you have any issues. In most cases it takes several weeks or more in storage before this occurs. But it's always good to check.

Thank you for your reply! The bike had just been fully serviced so hopefully everything works as intended.

I let it sit overnight, checked the oil for a gas smell and didn’t notice anything. I put about 30 miles on the bike today with no issues. I think I learnt my lesson just in time.

So much stuff to learn about these airheads.... looking forward to it.

There is an overflow standpipe in the carb bowls. If a carb floods gas will flow out the stand pipe and make a puddle unless the standpipe is also clogged. That is a lot of stars to align and you should not ride until your karma improves. It is possible to have so much flow through an open float needle that the standpipe is overwhelmed and gas goes into the intake. Might happen if the tank is very full (high pressure). again, if the standpipe is open you will see a puddle.

The bike and carbs can be working fine but one day a float hangs up in the bowl (the clearance is close) and when you go in for a sandwich and leave the petcock on you come back out to a puddle. That puddle is rather flammable. Always turn the petcocks off.

So much stuff to learn about these airheads.... looking forward to it.

This particular "stuff" is not peculiar to Airheads, it can happen on any piece of lawn equipment, home generator, or other brand of motorcycle. All that needs to be present is the for the engine to have a carburetor and the fuel tank located ABOVE the engine.

Gravity is your friend when you want to get fuel to the engine to RUN, and your enemy during storage. This is one reason why it's best to completely empty your Airhead's fuel if you live in a part of the country where Winter means 6 months in the shed.