Leaks gas from the carburator. - 2003 Yamaha YZ 125

is it fuel injected or carburated? if it is carburated look for leaks in and around the carburator it is usually the gasket between the carb and the manifild.

If is is fuel injected check the fuel you may have water in your tank. Also check the fuel in the tank of the carborated vehicle as well.

The floater of the carburator is bad(Needle). its leaking gas at the carburator and the gas is coming inside the engine at piston intake valves.
Replace carburator needle that stops the intake of gas at the Carburator.

First place to look is the float in the carburator my mower leaked a tank of gas when the float stuck

You probably need to replace it.... :-(

Sounds like the fuel pump isn't working, you can buy service kits though quite often corrosion will prevent you from removing the valves.. or it could simply be the fuel cap isn't venting, remove fuel cap and see if the engine continues to run!

Sounds to me like your float valve is obstructed by some debris. This is causing it to stay open and leak fuel. Better it leaks to your vent hose than it leaks in your engine and contaminates your oil.

You need a proper carb cleaning. Not some run in the gas tank sh*t. If the tank wasn't full when parked, chances are there is rust in the fuel system to get this out you need to disassemble the carburetor and thoroughly clean it.

Try not to ride the bike til you do this. It's a fire hazard.

The DPC7311 is a two-stroke demolition saw, there should be no standing fluids, oil or otherwise in the crank case to leak out. The reason it uses a 50-to-1 gas-to-oil mix is so the oil in the gas can settle on the moving parts and lubricate them.
If you do have anything leaking anywhere out of your crankcase you most likely have problems with your carburator in that too much fuel is getting into and filling up the crankcase.
You should also look to make sure your leak isn't coming from a crack in the fuel tank or from the carburator or fuel line and running down to look like it's coming from the crankcase.

Check the float valve. I suspect that you have a piece of dirt in the inlet valve.

Spray starting fluid near the carburator if equipped. It may be a leaking main gasket under the carb.If you spray and the engine turns off. It is a vacuum leak. meaning the main gasket under the carburator .