Got some sludge in the pan too (and what looks like a dead worm), but seems clean-ish up in the engine. I got a suggestion to do an old farmer's trick. Drain the oil, replace with kerosene, roll it over, don't let it start for about 30 seconds, let it cool down, roll it over again. Drain, put in fresh oil, run til warm, drain, add new oil.
Does anyone see anything awful about this that's bike specific?