layshaft gear removal

[mark]

just assembled the gearbox on my 55 road rocket and found that the layshaft is bent. I have a spare but would like to keep the original fixed gear which is in better condition and the original pair to the sleeve gear. My question is how is this gear removed, the parts book shows a circlip which is covered by the gear, what is its purpose? Is the fixed gear just a press fit?

Mark

[BSA500]

It needs to be pressed off and the new one pressed on.Found this out when I used the cluster from a c12 box as the lay and mainshafts are different but the gears the same and quite unworn as the little engine doesn't stress them so much.