Well I ported an 026 and it stopped running on the 3rd tank, not sure what happened. Ported an ms200t very recently, idled through a tank, as soon as I start walking to a tree it started rattling, I shut it off and then it was seized. Took it apart and for the life of me cannot figure out why it seized, but just put a stock motor back on for now bc I need the money!
I found a formula awhile back and I cannot fully explain it all, but you take your bore size and multiply that by .04% and .05% and the gap should be somewhere in between there. Some will say as long as it is under a mm its good but that is insane to me. .017-.030 I find is a good rough range to use.