Hi there, does anyone have any tips about the security of the nuts and washers that go on the bottom of the handlebar risers, below the rubber cushions? On the 450K0 I have found them to slack off under vibration; rather disconcerting. I've added some threadlock and tightened down, but is there something I am missing? I have the large collared washers on there and then a standard washer and nut. How tight should they be? Thanks