I started this a long time ago and others have done it without issue, I would say your case is a rarity. I had my bushes made and a couple were tight due to probably my not perfect measuring method (vernier) and manufacturing tolerance. I would expect the items you are able to buy in USA (not available Australia) would be of a better manufacturing quality.
I don't like the heating/freezing method of fitting, I have tried this with wheel bearings and the process felt grabby or sticky and a not smooth fit. I understand the theory and theoretically should work but I didn't like it and haven't used it since.
Anybody changing to bushings would do well do make note of the post listed below and think about my instructions in reply 45. I used a bench vice and socket without issue.
http://www.zggtr.org/index.php?topic=6061.45I think needle roller bearings (available from Kawasaki only) are a lot more expensive than the bushings.
Regards, Russell