Other things to check, fuel flow out of petcock, "screen could be pugged or faulty petcock, carb float needle, "restriction, adjustment" is it keeping the float bowl full, could your ignition module or coil be going bad yes, Ultima ignitions are dependable ignitions but they do all go bad sometimes

 

This idea of running out of fuel is interesting. I know what running out of fuel is like, and this didn't sound like that, however, I have been wrong in the past.
I'll look into the fuel cap venting, and petcock.

 

Everyone is wrong sometimes, comes with the territory... It may have over heated, but that could still be from starving of fuel.

Running out, yeah they pretty much cut off at higher speeds. With a vent problem, the bowl gets low, float drops, valve opens and if the vacuum in the tank is high enough it can suck an air bubble back thru the line, let a little more fuel flow and repeat. That will make one run lean and sorta feel like running out and cause a heat problem at the same time. Morale of the story - checking the cap and petcock is fairly easy and quick so that's where I'd start....

 

What brand is the ignition coil?

There has been some history of the cheaper coils acting like this when hot, so checking for spark the next time this happens is another option (if removing the fuel cap and trying to start back up does not work).

There has been some history of some of the ultima ignitions cutting out when hot, but that was years ago. Seems Ultima solved the problem a few years back if my memory serves me correctly.

Not doubting what has been said about the tank venting and fuel flow, just giving you some more to think about/check out. Good luck with the diagnostics.

 

I failed to ask specifically about the coil.

OP said it was Ultima ignition and new coil, don't know if both were new. For sure, the coils that come with those ignitions (as a kit) have a very bad track record.

 

I had a garbage Crane in the cone ignition that would overheat and shut off and fire up when it cooled off.

 

Yes, if not fuel, then electronics over heating would be my next thought...

 

 

UPDATE....
I rode the bike yesterday on the same freeway, at the same speed, all with no problems, no overheating.
My conclusion is:
It's not a fuel issue, nor a fuel cap issue, or petcock.
The only thing that was different from yesterday and the day before are the spark plugs. The day of overheating I was running a hotter plug. Yesterday I went back to the colder plug.

Thank for all the input. It's appreciated.

 

Interesting., So what plug were you running and what plug are you running...