My symptoms were:
Sudden onset of 'hard to start'
Return of 'cold natured'
Maybe some slight loss of power
Slightly increased oil blow-by
It wasn't obvious except for the difficulty in starting the scooter.
Luckily, the shop I took it too had 25% off on labor for the month on Jan and I just squeaked in.
They said I had 20% leak-down. I asked but they had not checked compression "because these scooters have a pressure release to make them easier to start".
Looking for feedback; is it a really good idea to replace not just the piston head but the whole 'upper kit' ? It is $85 vs $395