This is why you don't let someone else ride your bike! my mates dt got blown up because some clown didn't know how to ride 2 strokes. Mind it is a ratty bike and piston was probably packing its bags anyhow.
Looks like death ash to me, poor jetting will cause that.
Always Originate, Never Pirate!
@calum he had it running really rich. I told him I would adjust his oil pump but he wanted it rich and he was poring even more oil into the fuel. Silly geiser
How does the sparkplug look?
Ouch! Thought running rich would just cause excessive fouling?