"Try applying the front brake while standing next to the bike and rock the bike back and forwards, if they're loose (or knackered) you should be able to feel the play. (if they are, try replacing them with taper roller bearings, far superior & less maintenance intensive) but dont over tighten them what ever you do".

Mr T,

Where do you get the taper roller head race bearings from for the NSR?
The top one on the MC21 is (typically) an odd size.

I gave up looking for taper roller bearings and bought some standard ones from David Silver Spares.

Cheers

Roy.