Swingarm shaft Q

Aloha guys.

Recently, I took off my KZ swing arm from the frame to get the frame painted.

Why did I took out the swing arm? I plan to get Zephyr swing arm (not too sure which I'm gonna go with. 400 or 750. Yes, I know 400 is Japan only but I have friends there). But that just a plan. Anyway, while I was taking the swing arm off, I manage to hit my hand with a hammer several times and it still hurts. And that is my very question.

I have '89 ZX-7 which I'm rebuilding right now, same time as my KZ ( I need to go to Vegas soon and somehow hit that jackpot soon. Running out of my budget restoring both bikes). When I was taking off ZX-7 swing arm, I did not use hammer or anything. Swing arm shaft slid right off. But my KZ needed more than some persuasion (hence hammer hitting my hand more than several times). Is it suppose to be like this? I mean does it need to be hit it with hammer more than few times or it suppose to slid right off?

I tried search for some answer, but could not find anything. HELP!!

BTW, for my KZ, I plan to change all the bearing, stock or Zephyr swing arm.

Swingarm spindles can seize in the frame or bushes if they have been In a while, especially if it's not been touched for years , used in damp/wet conditions or pressure washed occasionally.
In bad cases they have had to be heated up, drilled or cut out.
If you only needed a few hammer blows you have been lucky and when everything is cleaned and lubed up it should slide back in by hand..