It's probably much easier to buy the left handlebar cluster from a similar-year but EU-spec 650. All EU-spec bikes have the hazards by default. You can either get a new one from the usual sources, or try to get a 2nd hand one from one that was in an accident and written off. It's also a much cleaner solution that way.
The other thing to be aware of is that you might need another relay to deal with the higher current, if your current relay is not designed to handle both the 2-way and 4-way current. However, information about whether this is required is hard to come by. Best is to look at your current relay (just in front of the battery) and see if it has something like ("T: 21Wx2" and "H: 21Wx4") on it. The T is the wattage of 2-way flashers (normal indicators) and the H is the wattage of all four flashers combined.
Last edited by BackPacker; 03-18-2019 at 09:51 AM.