Junk pwk is propably your whole problems

When I put my keihin on my 87 I loved it. I'll trade two flat slide 34mm keihins. One needs rebuilt, the other I have never ran. For 1 PWK 36mm-40mm.

James how many engines have you ran at .018 squish?  Or under .030 for that fact.     Just curious.   

That plug looks terrible. Its showing signs of massive overheating. Unless the black on the base ring wipes of with no solvents. What I am seeing is the plug is running so hot the fresh mix is flashing and baking onto the base ring, don't confuse that with anytbing to do plug wise yet. Its all from too much heat in the head. The plug can't transfer heat as fast as the alum head. So its the first thing to show overheating. From what your describing your getting preignition also, this is likely the cause of the wide open issue. For the record , a 18 cc dome can't really be cut to work with a big bore engine properly.
Just for kicks cut It the threads off that plug so you can see up in side. Where the porcelean meets the steel.

As far as the head good move lapping it. But you also need to check the top of the cylinder. The ruler trick is only good for a quick obvious issue. I'm thinking the top of the cyl is not flat or that the sleeve has sunk. Slightly causing some of the head gasket issues along with too much compression and preignition.

Not sure iceracer, how bout you? The one I'm running right now is at .043. By the way bud, I did state my reference for all to see, and also my disclaimer that I'm not a champion engine builder. I was just saying what I would do. Right or wrong I stand behind all my statements on here. I want this guys motor running right as much as anybody on here. I guarantee ya that. And I don't want any of his money, or any brownie points with my favorite builder by sending his cash there. I got that info on squish from gordan jennings book. He's forgot more about two strokes than most of us will ever know. I stated my freakin references and told the guy that that is what I would do. Now you can tell him whatever you want but you don't gotta go get sassy with me in the process.

Before dropping $80 on a carb bowl I think you should set the float height, and get the head done so your staying within temps, then adjust jetting if need be. THEN if she still sputters get the bowl see if it actually just needed to suck up more fuel or something else going on. 

Would going to 32:1, and raising the needle back up one notch help with keeping it cooler?

......................... I got that info on squish from gordan jennings book. He's forgot more about two strokes than most of us will ever know. ...............

Gordon Jennings looked at and worked on a lot of two-stroke engines in the 1960s and wrote about many of these engines in the 1970s for Cycle World Magazine.  Gordon was good at putting his ideas about how things worked on paper although many of his theories and conclusions to his observations have been proven wrong by engineers and engine developers that have done a lot of dyno and field testing on two-stroke engine.  I liked his style of writing and was reading everything that he wrote while I was studying to become an engineer.  Gordon Jennings pipe theory and formulas steered a lot of us including myself in the wrong directions for many years.  Initially I accepted most of his teaching as divine revelation.  As my engineering studies progress I started seeing flaws in some of his teachings.

I started reading SAE papers written by Gordon Blair and his students while I was also studying engineering.  The SAE papers were mostly research papers that presented theory and the testing to prove or disprove the theory in question.  At that point in my academic career, most of the SAE papers were over my head.  As my academic studies progressed Gordon Blair’s research was easier to understand and disproved some of the Gordon Jennings theories and conclusions.

If you really want to learn about two-stroke engine development, read the text books and SAE papers written by Professor Gordon Blair from the from the Queens University in Ireland.  Gordon Blair did research projects for all of the major two-stoke engine manufactures around the world from the early 1960s until his retirement in about 1995.  Gordon Blair did more during his lifetime to further two-stroke technology than all of the combined research done on two stoke from the early 1900s until his death a few years ago.  Gordon Blair’s engineering students are currently working for engine manufactures around the world today and continuing much of the research that Gordon started. 

Prerequisites for reading and understanding Gordon Blair's publications are an engineering background, or training at the university level in calculus, differential and partial differential equations, fluid mechanics, gas dynamics, thermodynamics, computer programming, and physics with and emphasis on statics and dynamics.

Racer as far a s the super bowl it could help some but the float level and size of you needle and seat will have the most bearing on fuel supply. 

iceracer i guess i may be dumb but i just though of it, if i am blowing headgaskets and have cyl gasses leaking into the cooling system that would raise the coolant temp and overheat. right. i just got my new gaskets in today waiting on my buddy to bring the base gasket home and i will insert the .059 gasket in and do a compression test and also recheck the squish. i did the math it should be around .062 but i will check it with the gasket and everything tight. and keep you guys updated. its just hard to believe that with the 40mm overside rad and the cms silicon hoses and using engine ice for coolant (20 bucks half gal) would still get this hot. maybe i will also look into a eletric fan and use the headlight switch to turn it on and off. might get lucky and high speed and low speed.

If you're blowing gaskets you've got a problem. Just need to sort out exactly the cause of the head gasket failures.

1 turn counter clock wise is the stock setting

thanks for everyone's help, i will keep every one updated on how it does at the dealer ride, whats cool about the dealer ride they let bike on the track with the quads so i will have some vids of me smoking some bike soon.

Thanks motorgeek. I think I might start a thread on the books. Hopefully you'll chime in there.
My apologies to motorman since I gave him some bad advice on squish. Luckily you guys got in here before any more damage was done.
Iceracer. My bad dude.

Not trying to thread jack by any means but this dude just gained some major respect points in my book. Swallowed the chill pill, admitted he was wrong and even apologized!! WOW!!! Rock on dude!!! May the 2-stroke deities bless you with many many more years of happy riding, perma-fresh top ends, and zero minutes of down time for the rest of your days

Thanks guys. If your hungry enough, crow ain't all that bad to eat. In my circles, I'm used to teaching about mechanical stuff, on here I'm getting used to listening and learning again. But Im liken it.
BTW I run engine ice in mine, and I haven't taken a temp reading, but it does seem to run cooler on the trails. I'm just runnin a stock bore 1987 250 motor. 93 pump gas. I keep her screaming on these KY hills. I can't understand why it runs cooler with the engine ice, but I really think it does. I also run my main jet right on the border of being too rich for the same reason.