Re: engine siezed - fix or replace?
what were the engine operation parameters when it seized? did you warm up engine a little before going to full throttle-2 strokes can cold seize.
how much oil mixture ratio and what type are you using? i strongly recommend 32:1 using klotz supertechniplate or maxima 927....no more or less for now.
pull the head and check to see that the pins in the cylinder that prevent ring rotation are secure...sometimes they pop out and get spit out the exhaust and then the rings rotate and catch on a port.
some more info would be appreciated. also check idle mixture by starting engine then closing the fuel valve and see how much it speeds up. it shold speed up 200-300 rpm just before it dies...if it sounds like it is speeding up a lot you are too rich and if it speeds up or doesn't speed up at all you may wish to lower the e-clip on the needle valve one notch to richen the mixture.