I am surprised you dont like the suspension of the 250F, that is one of the best traits of it...
I will be riding a 450F soon, so I cant really tell you what to do...But if you are a Honda fan, you wont go wrong with the 450F. I'm sure the bike will be as easy to ride as your CR250. I rode my 4stroke and some 2 strokes and had the same conclusion as you, it seemed to not take as much effort with revving up and shifting all the time. I dont think it is because of "lacking power" because the bike pulls, but the 450F is sure to pull harder, at least I would imagine. IMO, the 450F should have the same 4stroke ease as well. I dont think you should hesitate, pull the trigger!
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and dont get me wrong, 2 strokes are great, it depends on the rider and what they are looking for.
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