A MC11 also owns me.Mine at 13,000 kms. displays some of your operating symptoms.Mine needs pistons and rings to bring the compression back up to where it will cold start and operate properly.Check your compression.It can be quite low on a 2 stroke,maybe 7 to 1 at cranking speed and they will still run alright.Also on my MC11 after long term storage it developed a bad wireing harness ground.It is located just foreward of the battery,remove the bolt and make all surfaces shiney.On mine the alloy chassis side was dull grey, alluminum oxide is non conductive.With out electric start bad chassis ground can sneak up on you because there is no real high amp draw to reveal it.Back to the pistons ,they are hard to find so I am trying to fit 86 kawasaki KX125 pistons now if I can just find the gaskets all will be good.Stay posted and good luck...Lee