This has been a somewhat painful (more my ego really, but I'm not made of money either) learning experience, but I try to be a glass half-full kind of guy, and I think I have learned a great deal from it.
I think it was an expensive,unwanted necessity.
Andy, I am always open to yours, and the other senior members here's critique (you all know who you are). Most of what I know about performance 2-strokes comes from you guys and this site, and I very highly value all yours opinions.
On this point, lesson learned.
I think I am done with plug chops tests too, as you have previously stated you don't do.
Thanks for chiming in by the way, I was hoping you would 
Thanks for everyone else's responses too, those that have been following me on this 'disease' I seem to have caught lately.
I have spent the past few days wondering how to get it fixed and how to do it the least expensive way, but today I spoke with my buddy with the CR480 that we brought back from the dead, and he asked how much a new cylinder was.
I hadn't thought of checking because of my $12.56 Kawasaki main jet total rip-off experience, but it turns out, at Motosport, a new OE cylinder is $305.00, and a piston is like $46.00, and both are in stock.
So I think I am just going to get those coming, and start over.
So after the new parts arrive and get assembled, my new plan is this, and please please let me know if I am still not going in the right direction, cuz I still have a YZ250 that has the same symptoms that the CR had, and I like to learn from my mistakes...
My plan is to put the stock jets in (125, 50), and start the tuning process with the needle jet and it's position.
The bike ran noticeably better to my son, who has zero experience, and to me, when I dropped the needle one slot. It was better on the run-up to WFO, no sputtering.
Then I burned it up at WFO.
The coolant issue I am still considering, but am tending to believe it is a non- issue right now, only because we put 7 hours on the bike 2 weeks ago with no problems so...
But I'll monitor the situation closely and report back when I get some new parts installed.
