You need a special socket. It's similar to a CV joint socket for cars but smaller. I do not think you will have much luck finding one at auto stores so you will have to either get one at the dealer, order one online or make one yourself.
You could take a thick metal pipe of the same diameter as the nut and cut the end leaving four notches, but that might be a lot more work than you are willing to do.
Dennis sells socket sets at that will do the swingarm and frame nuts. It looks like the site has been down, though.