Duane, sounds like you missed one of the vacuum lines on the petcock. It's easy to put one of the small ones on the wrong place, there's only one correct spot, I believe it's on the front of the petcock (towards the headlamps). Then there is another to the left if you are looking forward at it.
I've experienced the same thing after taking the tank off, I'll get about a mile down the road and it dies. Wait a few minutes, fires right up and same thing. Turned out the lines were on wrong. There is a stub hanging down from the petcock dial that looks like a vacuum line...it's not.
Only thing I can think of......
The oil in the intake is normal, as long as it's only a slight amount....like you need a paper towel to get it out, not just your fingers.
I'll go rack my brain on this one....puzzling.