I'm sure there are other sources. You should probably be able to find them at www.denniskirk.com but you'll pay more.
Personally when I need bearings, bushes, oil seals, fork seals, water pump seals and other mechanical seals, - I go first to an industrial bearing supply house. Many times, they will stock a suitable replacement at a fraction of the MC dealers price. Usually, a bearing that may cost me $30+ bucks through a motorcycle parts supplier might only cost $7 through the bearing supply house.
Just make sure you are getting the right part, not just the same dimensions. Sight unseen - the supply house may sell you a seal with a steel outer/rubber inner instead of a flexible type, which could fail if the OEM part was plastic/rubber inner/outer.
Look up in your area for a bearing supply house. Best to bring the steering neck with and the old bearing parts. Have them measure them up, and they should be able to get you a suitable tapered replacement set.
They basically will take the inside dimensions, outside dimensions and depth and cross reference against their stocks. I don't remember off hand what the CB450 dimensions are. I usually clean them up and repack them. If I were to build a racer I'd probably go with tapered roller bearings because they provide more surface area than ball bearings and more solid feel.
I know the CB750 has the same steering neck and triple-trees. I recently swapped a set out on a project bike with no problems.
Personally for road use, I have no problem with ball bearings. I find they offer more road-feel without sacrificing any safety, if maintained.
My local bearing house is Berry Bearing Co. They are a national outfit. There is probably one in your area - unless you are far from a major city.
Jordan AkA polishbeer
