Yes they can be loose, not poke them out with your finger loose but a light tapping with a socket loose is not that uncommon. Sometimes they are tight but that's normally corrosion keeping them in place, the primary drive roller bearings in my experience are not that tightly fitted.
Whilst the D6B-A marking isn't an indication of colour, it is an indication that all the locations marked with that identifier are the same colour, so if you can identify one you've identified all those locations. Look on the edge of the bearing and sometimes you can still see the colour they print on there. It's on the very bottom of the half circle and right on the edge.
look on the back of the lower crankcase, it should have 5 letters stamped into the metal, let us know what they are. If nothing else they'll at least reduce the colour choice to 2-3 colours. On the crank are numbers and letters, 5 numbers, 4 letters, if you can see them let us know what they are. On the rods are a number and a letter, list those. That should give us enough info to identify the shell colours.
Certain colours are difficult to find these days, I have some 400 shells if you get stuck. Including some really rare colours like blue and red. Don't buy genuine Honda roller bearings for the primary shaft, just buy the same make from a bearing supplier, number is stamped on the old bearings as is the make, half the price, same quality. I also have some primary damper rubbers and the primary chain for sale if your interested, whereabouts in the world are you if English isn't your first language? Postage may be a problem due to expense.
