Kawasaki Forums - 1600 won't start/run after sitting

I'll try to lay this time line out the best I can for you guys this bike is kicking my butt.
The bike is a 2005 kawasaki vulcan 1600 classic. it was my father in laws the bike had ran very well and always taken very good care of. It was parked and sat for 4 years. I decided I wanted to buy it and that's where we start.

It sat with fuel in it. I drained that. then the pump was stuck. I pulled the pump. soaked it in Kroil. After some tapping it freed up. (yes maybe I should have replaced it but I'm a cheap *******) put it back together added new gas she fired right up. clutch was froze freed pretty easy.

Things were fine. running well. Except the next morning the "cold start" (80 degrees) was kind of hard even with the choke cable pulled. it was back firing and popping. finally took off.

The next morning. Mind you only 15 miles total. It wouldn't start, backfiring and popping through the intake.
later I pulled it apart suspecting a fuel problem. I can still hear the pump disconnect the line turn the key and it primes. i pulled the injectors to see if crud had got in them. Didn't see anything. So I put it all back together. It fired up and ran fine. ran sea foam through it and about 10 miles.

Next day hop on WON'T START back firing through the intake again. so I did it all again pulled the injectors cranked the bike with them out they seem to have a good spray.
After all this I did finally get a new fuel pump. It was just the pump and not the whole housing setup. After i put that in it ran great for a fewdays then same thing. Backfire through intake and seems to be running lean.

I'm sorry if this got long winded but I wanted to give you as much info as I could.