Welcome to the Super 9 family. I looked at the pics you posted on 49cc scoot and I gotta say that I very much doubt that kymco will replace the engine for a couple reasons. First the bike is 12yrs old and the model is discontinued (even though the engine series is not), but even more so is the fact that the damage/sludge isn't a manufacturer defect. I suspect that the bike. Was stored outside and probably didn't have a sparkplug installed/loose plug or if it's an LC perhaps a seal or packing let go. Either way, it comes down to an owner (not you) related maintenance issue, for which Kymco will probably not be willing to cover (even though it's really no skin off their butts as they made like a gazillion SF10 motors and only cost them like $10 per unit) I hope you luck. If I had a cylinder and piston to donate, I would. Keep us posted and we'll keep our fingers crossed.