Soot on spark plugs

I'm assuming you mean codes P0300 and P0301. Black soot on the plugs is usually because the fuel system is running 'rich'. This is when the fuel/air mixture going into the engine has too much fuel in it. Changing the spark plugs was a good step to take but it won't fix the problem.
When was the vehicle last given a full service? Something as simple as an old, dirty air filter can cause problems.
If you are not familiar with working on engines take the vehicle to a good mechanic and get them to look at it for you.

No spark at the plugs ? Are the plugs fouled with wet fuel or black soot ?

The black soot is carbon from the gas usually caused by too much fuel being burnt. Incorrect fuel to air ratio. Take vehicle to service center and have set.

check for oil gas mixture or its bad rings

black soot is overfueling. And as it is a trail bike operating in dirt and mud conditions I would be looking at changing the air filter first. Change to a hotter plugs may help (select plugs up in the heat range ). Check reason for extra fuel ( choke flapping on or float level )

Here's a look at spark plugs and the causes.

A good place to start would be to remove air cleaner assembly and give it a good wash and service and take a close look at choke assembly/lever to be sure it isn't sticking in on position, while trying to run it with air filter off..

the black soot may be old plug wires that should be replaced chances are the spilled oil caused the engine to miss fire setting off the check engine check the inside of the plug boots and plugs for oil.

The guy with the same problem..Your leaving your enrichner (choke) out thats where the 2000rpm and soot comes from...Original fellow I think you may have an intake leak around your manifold or carb.