Mirage GT drum sprockets vs v2 sprockets

Hi,

I bought a GT upgrade kit for the Mirage drive (plastic sprockets) on my 20214 AI a few years back but am only now
putting my drive back together with the GT upgrades (life got in the way ) , but the drive chain won't go over the GT drum sprockets, even though the pitch of the sprocket teeth appears to be the same (no such issue with the original sprockets and the same chain)

Anyone else had this issue? Any suggestions for a solution please?

_________________
Simon

The solution was to hit the chain harder with the rubber mallet (something I'd avoided at first for fear of damaging the bearing faces). Pretty poor machining tolerances and there is a lot of friction as the drum turns due to the chain sticking.

_________________
Simon