yes just cover off & easy swap, by memory just be careful to locate the spring clamp thing that puts tension on the gear to make it wind out & engage with intermediate gear, also with the return spring you'll have to pull it around a bit to clear the clutch basket to locate it on the peg.
Just this week replaces a broken shaft on an XT125 [with an ag200 shaft--same except has a piece to operate the decomp cable by the looks].
Guy has an XT200 & XT125 on the farm--both with crook ignition--125 ran for 5 then stop--walk home then starts GRRR, suspected source coil which i changed for [another crook one from the wreckers] which then had me chasing the box & top coil--long [few days] story but looks like it had two problems [box plus bottom coil], could tap the box while running & would misfire every time plus with a meter hooked on the stator source coil red & brown i could watch it break circuit after a minute or two--flick flick as it thought about stopping then 'bam' open circuit, that's on ac voltage not resistance 'but with it running'. funny [not] thing is, with my [well damped needle] on my peak meter, open circuit & the needle damping about equaled the motor rolling to a halt but my 'cheap' multi tester on AC with next to no damping showed instant flick of the needle.
Also--XT200 purely turned out to be the pulse [trigger] wire double connector had lost it's hook to hold it engaged & the connection pins had been tweaked & [by accident] found it i touched the wired near the plug she stopped, ended up just tweaking the connections & cable tied the multi plug engaged. Luckily i have a wrecker [dismantler in this pc age] that lets me grab a couple of boxes & stator coils or complete plates which makes life easier. The 125 has a history [$700 at a shop i believe] chasing ignition issues over the last couple of years--kicking back, took teeth off gear behind clutch & intermediate gear, broke kick start shaft, you name it. Luckily i'm retired [just tired!!] so have the time & not gonna give up but i'll 'let ya know if it comes back'. Sory about the essay [story of my week] Cheers [tears]