If you've got an engineering workshop near you, they'd be able to run a tap down the bar ends. I had the same dilemma, as after market weights that are as heavy as the Fazers are really expensive. Maybe you could hire a tap and die set. You need a 16mm tap @ 16 TPI (threads per inch). Initially I was told that it was necessary to run a 15mm drill bit down the bars, which have a 14mm inside diameter, before tapping them, but this has since been proved unnecessary. Good luck.
I live in the south where workshop time would be around £75 an hour, so expect a charge for half an hour, unless you know someone. I wouldn't have thought the average set would include a tap that large, but don't really know that as fact. That's why I suggested the possibility of hiring.
If you're anywhere near Exeter I had a set of Renthals tapped out to take the OEM bar ends for £20.My own experience is that the weight of the OEM bar ends does help prevent vibration felt through the bars, I could easily feel the difference between OEM and lightweight aftermarket which is why I got the bars tapped.
Oberon used to do very heavy stainless end weights that didn't need the bars tapped, the just bolt in with an expanding bolt setup.Personally, I've tried various setups with no difference in vibration at all. I'm currently using R&G weights that screw into the standard bars and I can't feel any difference in vibration.Jim.
Bollocks
Chinese so probably made of cheese. I would never buy anything other than HSS taps and dies, even for occasional DIY use buying cheap is a false economy. If the tap breaks in the hole you will be in a world of pain....