Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
Definately 30mm as already posted.
Ted,I had problems on the CB400 and also the CJ250T with two different brands of tapered bearings.The issue seems to be that the upper bearing is simply thicker than the original so reduces available thread on the stem.Bottom bearing with spacer worked out correctly but top bearing on both caused the problem.Will be keen to see if the ones you have will work better as it seems crazy that the bearings aren't simply interchangeable without issue.No other bikes I've worked on have had an issue so guess it's just on some models that things don't fit nicely.Cheers,Andy
If I can find the races off the set I bought in the 80s I'll measure the top race and see how it compares to yours, can't do that with the bottom as Bryan says getting the inner races out is problematic but the top race will come out if you lever it.
What I can't get my head round is that the bottom ball bearing race is approx 13.5 deep. So if the bottom bearing is 15.14 mm deep why does it need a 4 mm spacer as that would raise everything too high as has been mention by others ?