I'm betting on a fuel delivery problem. How did you test the petcock, Put it on prime? Anyone here will tell you that the eom petcock on these bikes are all the way around the world bad.
I wouldn't just toss the bike, they are the VW of motorcycles and the guys here will help you get it up to par in no time I guarantee it.

Have you tried adjusting the idle and pilot air/fuel mix screw?

savageLYFE wrote on 05/29/14 at 05:59:50:

What does the air filter look like?
a wet filter will act like a choke too.

You seem to be a thinking person & I dont want to offend, but I didnt see
WE put new gas in it

I almost wish you would say the gas is not new, because thats sure sounding a lot like old gas,, & OHH what a cheap, easy fix That is!

Just as a precaution,... dump that new gas into yer' car,... and try new gas again, from a different pump...

It has happened that people bought stale gas,, or worse, accidentally pumped diesel... and gone through weeks of frustration trying get their bike to run right... (one guy, found out the station accidentally filled the regular tank with diesel, and it got into a bunch of cars)...
Just as a precaution... you might try it...

If not,.. I'd guess there's still a jet or passage clogged...

A hotter spark plug won't help anything.  A hotter plug does not make a better spark....it retains more heat in the ceramic insulator so that you can burn off deposits......unless your plug is black and sooty or fouled going to a hotter plug will not help.

A high rpm engine would most likely want a colder plug to account for the fact that the engine is spinning really fast and firing often.  A low rpm engine would want a hotter plug to retain more heat in the tip of the plug.

The new stock plug should work to make the bike idle for a long time....even if there are jetting problems and the bike is too rich.  You need to be careful about putting too hot of a plug in any engine - if it gets too hot it can burn the electrodes off, and that hot spot before it burns away can often can leave a divot or hole in the piston crown.

Y'know, both my Suzuki singles have exhibited the same problem. In both cases it was an o ring in the carb needed replacing. The float needle sits in a brass seat. The seat itself is removable from the carb body and is sealed by an o ring. Over time the o ring starts to leak. Fuel can flow between the carb body and the brass insert, through the leaky o ring, into the float chamber, bypassing the needle which is supposed to be controlling the fuel level. So it runs really smoky and rich at idle because the fuel level is as high as it wants to be, overflowing the float bowl. At higher RPM the engine can keep up with the fuel leak and it runs ok. Slow down, bad again. I noticed the choke making it run better, too. I hope you have the same problem, it's a cheap and easy fix   . Good luck man.