STOP! I want to save you from
a lot of frustration and a little bit of money!
Take your right crank arm and bolt & tighten the CBR spindle into it (yes I know it is undersized diameter). Add a few of the CBR Delrin spacers onto the spindle and push it through the BB and see how close the chainrings are to the chainstays. Add or subtract the spacers until you have 2 to 3 mm gap between the middle/ large chainrings and the chain stays.
Then hand press the left crank arm on the spindle parallel to the right crank (do not wrench tighten) a measure the distance from the pedal ball to the pedal ball of the left crank arm and the left chainstay. In a perfect world this distance should be 6 to 8 mm (considering that the compression of the crank arm onto the spindle will be 2~3 mm if the cranks have never been previously abused aka: over thighened).
Next, pull everything apart and measure your current spindle, and calculate what your "perfect spindle" length should be!
BUT STOP!!! At this point you have options! You can go find/ buy a 17mm spindle that is the correct length, OR go find bearings with a MM OD that matches the Klien BB with a 5/8" ID to match your CBR spindle! Yes, oddly enough these kind of bearings exist! I have no clue where over on "your side of the pond" they can be had, but over here in Kalifornia there is a GREAT bearing company call Euro Bearing (yeah kind of funny, huh) that could at least steer you in the right direction.
Good luck and I hope you post up pictures
CBR spindles are 5/8".
If you have a CBR BB you'll find the bearings have a Metric OD and a custom ground imperial 5/8" bore.
You're right, custom bearings and grinds are available from bearing suppliers, but they're not especially cheap.
I think finding a 17mm spindle may be more economic.
Always worth looking at
https://www.kleinspainted.com/--one-stop-klein-shop.html to see what they have in stock.
thank you for your reply , i have managed to get a 17mm spindle with correct taper on Ebay from the States