84 aspencade carb issues

[tongy66086]

Hello all.
Today, I drove down to southern Kansas and picked up another 84 Aspencade. I don't intend on making this bike one of my riders, but instead it will be a parts donor bike.
I rode it home, a little under 200 miles.
When I talked to the guy, he told me that he thought the carbs were gummed up and that the tank was getting a slight varnishy smell to it. He said he drained the gas that was in it, filled it with fresh gas and put carb cleaner in the tank.
I looked the bike over, and saw enough parts that I could get a return on the 350 I spent for it.
I took it to the nearest gas station, put some Sea Foam in the tank, and filled it up.
The thing ran but did a lot of missing and horrible acceleration.
I got on the interstate highway, and I could get it to 80 on level ground, but when I hit even a slight hill, it would go to 60 wide open.
After about 100 miles, I stopped and filled it up again, again adding Sea Foam.
I have to say, it seems to be running a lot better, but still has terrible acceleration. Also, it still has a miss to it, but not like when I had first taken off on it.
What acceleration it does have reminds me of the cars back when I was a teen, in the old days, of having the vacuum advance hose either off, or the advance not working at all.
Does this still sound like carb issues, or possibly something else I need to look at?
Thanks a million for any help and suggestions you might have.