Hi and welcome
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Slight vibes are pretty normal and can't be eradicated completely by changing the bars, end weights or whatever. That said, the standard bars often get changed for Renthals (758s are the most popular) because the latter are stronger and have a more comfortable drawback angle.
The earlier models were a bit more buzzy at certain revs than later ones. Yamaha set the fuelling a bit lean at part throttle which can cause lean surge and vibes. This can be improved with a bit of carb work.
You can keep vibes to a minimum by synching the carbs and generally making sure that the bike is well-serviced and set up as it should be.
Mike