Two stroke I hope. I had a KTM 250SX thumper a few years ago and was underwhelmed. I'm from the 2 stroke era. Still have a "03 KDX 220 and a Yamaha DT200R road/dirt bike but my riding has wound down. Could never warm up up to the thumpers really, so the SX, although a technical marvel, was short lived. This is a bicycle forum so I will cut it short at that, as I could talk about dirt biking all day (at least from the retro perspective ... I'm from the DeCoster, Mikkola, Hannah era). Closing thought ... off road dirt biking was the the most rewarding and fun sport I have ever participated in, bar none ... my biggest lament is that I can no longer do it due to age (sigh), time, and lack of accessible riding areas.