Ah,... where the exhaust pipe joins the barrel there are two M8 nuts (per cylinder) holding the exhaust pipe onto the barrel. (14mm? socket required)
You need to remove the entire exhaust system. You can leave the mufflers (end cans) attached to the main pipe (expansion chamber).
Feel free to make full use of the Parts Manual on NSR-World.
Then with the spark plugs out (and gearbox in neutral) it is easy to turn the engine over by hand (using the kick starter) while you look up the exhaust port of the barrels, perhaps with the aid of a torch.
When the piston comes up you will be able to see the condition of the piston skirt. Well part of it.
When the piston goes down you will be able to see the condition of the bore. Again, part of it.
That is usually a good enough inspection when checking for a partial or full seizure.
And yes, this involves lying on the ground with the back of your head hitting the rear of the front tyre as you peer up the exhaust ports,.. kinda thing.
Kick starter in one hand, torch in the other, whilst operating a digital camera in your mouth. Standard 2-stroke maintenance check 1(a).
Oh, and if you have a reasonably strong grip ( I can see the jokes coming already ) you can rotate the powervalve motor pulley by hand (with the ignition key off) to raise the powervalves to get a better look up the exhaust ports.
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[color=#808080][size=9]Yes,.. I too know how to waste Time and Money,...