T100 speedo drive

I need some help please. The speedo drive on my T100 was removed and then reassembled as per the manual. I reconnected the speedo cable after front wheel assembly and I the wheeled the bike back off the bench and it snapped the cable. The drive moves around until it hits the stopper on the forks and that movement is enough to snap the cable! I've ordered a new cable and reassembled/greased the drive and it still does it !! Help please as it's driving me nuts. Thanks

 

Cheers keith