For those few unfortunate ones like me who have the bike vibrate - or I should say 'shakes' - around 3.5k and 4.5k rpm, I believe I have found a solution after over a year and 16k km.
Before I hand the answer to you, just to recap:
- to me, the bike 'shakes' more than 'vibrates' at that rpm range, the most intrusive is when it's full tank. This happened since day 1 with stock handlebar and bar-end weights, and I told the dealer's chief mechanic who told me it's because of the plastic tank, and we all know it's BS.
- Hoping some improvements, I then changed to Magura handlebar and no bar-end weight, but hope was dashed and the 'shaking' remains. I'm convinced this is beyond the normal vibration from a single cylinder bike.
- I had succeeded once by turning all the screws on and near the handlebar areas to the torque level according to the repair manual, but could not find that sweet spot again after I changed something.
- It did get smoother with age, but it was still annoying, it really took out the fun.
- After I discovered the bashplate cracked at the bolt area, which I hoped it was the cause of the shaking, the dealer replaced with a new one, but the vibration or the 'shaking' got worse.
- I took it back to the dealer, had them compared to their test bike, and finally they agreed reluctantly that there was something wrong, and called the chief mechanic of Yamaha Germany in Stuttgart to come take a look.
- He looked, insisted the bike was fine, but did agree the 'vibration' was too much in that rpm range. So he asked my dealer to: 1) adjust the EFI, and 2) give me a new bar-end weight which is different from the stock. This bar-end weight allows a long screw go through (not thread through) and even attach to the acerbis handguard anchor inside the handlebar.
- The adjustment and the bar-end weight helped, but the 'shaking' is still noticeably there.
- Then I stumbled onto this:
www.vibranator.com. Funny name, but I thought I would give it a try with USD70, afterall it claims it has technology from helicopters.
- I installed the vibranator without the bar-end weight as I thought if it works on a helicopter, I need no bar-end weight.
- This vibranator alone does two things: 1) it kills whatever resonance at any rpm range, and 2) it shifts the 'shaking' range to a bit higher range.
- I uninstalled it, and reinstalled it WITH the bar-end weights this time. Smooth!! I no longer know where the 'shaking' range is or if it exists anymore. I rev the bike from idle to 6-7k rpm and I notice no annoying 'shaking' or wild vibration for that matter. It still works at full tank too, which is the ultimate test. Now as if the bike gets a new life, and I find a new level of fun with it.