Ktm 125 sx 08 stuck in 1st gear

You have a bent shift fork and possibly something else going on. The engine will need to come out of the bike. Remove the top end, the flywheel and electrics, the clutch, the shift mechanism and kick starter and a few other parts. THEN you are ready to split the gearbox to get to the crankshaft, gears and shift forks.
You will need an impact driver, flywheel puller, case splitter, torque wrench and factory service manual, plus the normal screwdriver, pliers, etc.. Alternate to the special tools is taking it to the dealer and say "Fix it". I often tell people to take it to the shop just so they don't get into such an involved project and they now have a knowing eye and experienced hands working on the problem.
The repair cost will probably be $800 or so.

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2009 200xcw
The bike downshifts OK, when in 1st it wont upshift normal. If you flip shifter up it will go into other gears but sparatic. No fall or anything out of the normal before this happend. The bike only has 23 hrs. on it.