TB sync pointless for high revs!?

So I have a weird issue I noticed recently. When running high revs say over 5k or so the vibration gets a bit insane especially at higher speeds to where my Ram mounted phone vibrates quiet a bit not to mention the rest of the bike. If I hit the clutch and rpms drop it mostly goes away. So I'm reading random info on the net that a TB sync is pointless for over 4k rpms sooo if thats true it won't help here. I have 69k and have NOT checked the mounts (where are they in the service manual?) and wondering if maybe that's it. I recently had a oil situation where I started burning after the formula changed (other thread) but now running Castrol MC oil full syn and wondering if maybe the clutch is slipping slightly or the plugs are coated in oil and thus misfiring slightly?

Quote "TB sync is pointless for over 4k rpms sooo if thats true it won't help here."

That is incorrect. Extreme example: one cylinder does not start opening until 1/4 throttle because it is that far out of sync. Think there might be a vibration problem? I'm not saying that sync is your problem, just that sync can cause your problem.


What I would do on a bike with 70k and vibration:

Check and adjust valves

Change plugs and check compression or do a leak down check

Sync TBs

Check chain and sprockets for excess wear and proper tension.

Tire balance, especially if the vibration is worse at 5k RPM in higher gears than it is in lower gears

Found them today and did the major engine mount bolts. Two out of three turned almost a full turn and most of the major vibration is gone! TB sync is defiantly next to smooth her out even more!