https://www.ducati.com/gb/en/bikes/off-road/desmo450-mx. One small detail in the Tech Spec, pistons changed every 45 hours Andy
Sure that’s an MX thing I don’t know enough tbh. Would that be an engine out job or accessible as it stands…
Pretty typical piston life for a MX race bike. They get an absolute hammering. If the bike is used for pottering around woods it would last many times longer than that with just a gradual drop off in power, and worse starting to give it away.