WRONG.
You fail.
I LOVE 2-strokes, but I will give credit where credit is due.
On any given track, or any given trail a YZ250F will be the better bike than a YZ125 period.
You throw around maintanance costs. Yes the 4-stroke is more expensive to rebuild, BUT it doesn’t need to be rebuilt nearly as much as a 2-stroke does. You talk about how expensive an exhaust is, so leave it stock, duh. You think a 2-stroke needs a piston/rings once a season? Hrmm…well you obviously don’t ride a lot, or ride the bike on the pipe a lot. Maybe your CR500 you could get away with that but not a 125 that gets ridden a lot, no way. I could go about 2 months, maybe, then it at least needed rings.
Then lets talk about technique to ride. What do you think is the easier bike to ride? Hands down the 4-stroke. The only way to get a 125 to move is to rev the shit out of it and ride the clutch constantly, unless you weigh 50lbs. Go lug a 125 around for about 5 minutes with a beginner on board. It will foul the plug and stall. NGK B9EV’s can get expensive.
Your CR500 has a ton of power for sure, but a bike like that can be a handful to ride, and will literally beat the shit out of you in 3 laps. One bad blip of the throttle on the face of a jump and it’s all over.
Let’s talk about gas costs. Pull up to the pump and gas up your 4-stroke. 2-strokes need the pre-mix which isn’t that big of a deal, but it does add up after a while.
Like I said before, I LOVE 2-strokes and wish the AMA would have picked a better displacement for the 4-strokes, but I will concede that a 4-stroke is a better bike. It should have been something like this:
125cc 2-stroke/200cc 4-stroke
250cc 2-stroke/350cc 4-stroke
With displacements something like that all the manufacturers would still be making them.