I bought the bars and risers from Bikermart.co.uk. Search Vitpilen 401 and you’ll find them.
The bars I chose, and that were supplied have a very narrow internal diameter so I also bought some bar end weights also from Bikermart.co.uk and used the smallest 11mm adapters. I’m not sure if the official bar end mirrors will fit. I just used some bar end mirrors from eBay and clamped them to the weights and they’re fine with no movement or vibration.
I then put Renthal Kevlar grips on.