I've been trying the whole day long to understand why my new DRT spitfire cluster couldn't accept the 21 needle bearing. Brand new shaft (an old one too for comparaison purpose), a complete set of sip needles (2/2,14mm, those for PX...) and nothing. I just can't shove in place the shaft surrounded by the complete set of needles. Beyond 18 there is not enough room.... I've never had such an issue... I've compared 2 clusters and obviously inner track of the drt's has a smaller diameter than a standard piaggio's cluster. What can I do?