'78 kz650sr w/ strange 'lean.' Any thoughts?

I just got my first motorcycle...a '78 kz650 sr.
When I hit the rear brake the rear end of the bike sort of pulls to the right. It's a strange feeling and worries me a bit if I were to have to brake hard. Feels like the back wants to lay down and scoot up to the front on right. There's also a slight sensation of pulling to the left when on the accelerator. A friend of mine thinks maybe it could be worn swingarm bushings?? Wanted to get some other opinions before tackling replacements. Chain tension seems uniform. Not really much play in swingarm that I can tell. I'm not sure what else I should look for...really new to the motorcycle world and ready to learn all I can!
Thanks for the help!

I suspect that your rear wheel is mis-aligned. It could be due to worn swingarm bushings, or just a simple incorrect adjustment of the rear axle. Have you verified that the rear axle adjusters are at least set to the same tick mark on the swingarm?

One of the adjusters is on upside down, so can't see the tick marks. Measured exposed threads of adjusters. They were w/in a thread of each other.

maiken wrote: "... A friend of mine thinks maybe it could be worn swingarm bushings?? ..."

The KZ650-D1 (1978-SR) uses 4 needle bearings in the swingarm instead of bushings. Ed

Honestly, I don't really trust the markings to get it right. I like to use a long straightedge to check that the rear wheel is parallel to the front. You can have the tick marks aligned perfectly, and a little wear in the swingarm bearings will cause the swingarm to twist inward on the drive side. The chain pull under power will cause it to twist to the left, then when you let off the gas it relaxes. Hit the rear brake and guess what you get? Right turn, Clyde.

i measure from center of swingarm pivot bolt to center of rear axle on each side.
if bike has a center stand you can raise rear wheel up off of ground then grab top and bottem of wheel and try twisting back/forth to check for slop in swingarm

Makes sense. I'll check for alignment and slop in the swingarm again using the suggestions.
Is replacing needle bearings a job a novice could do? or would you recommend finding someone else to do it (if that's what it needs)?
Thanks for the feedback!