gs 1100 swingarm on 650, what wheel bearings?

I am getting ready to install my new swinger on my 78 659 c2 with mag wheels. I understand I need to go to 20mm bearings. Could someone give me a specfic link or part number to which ones I need? Thanks

Your using the kz wheel I assume. Just measure the outside diameter of the stock bearings and check the inside diameter to see if it is 20mm. If not I believe you can special order from allballs bearings.

I would love more info on how to do this swap. Photos and part #'s would be awesome!!!