On the modern bikes I started big and kept going smaller, KTM 525 then a couple Honda 450f's KTM 200sx Than a couple Honda 250f's threw a KTM 144 in between those and now am on a 09 KTM 150. The 250f's are easier to ride at speed without a doubt but for a grin from ear to ear the fun factor is all about small bore two stroke. After really learning how to ride one and learning to keep it pegged at all times, I can't believe how fun they are. A bunch of my friends ride 450's and in some places they have the advantage but all in all I can out brake,out jump, out corner them and..... it pisses them off so much it makes it even more fun if thats possible!
Two strokes rule!!!!