Throttle body synchronization is less important on the 650 than the 1000.
This is true but "less important" does not mean "not important".
How can that be? Once you pass about 3000 rpm, and/or have the throttle blades open beyond easy cruising levels throttle body synchronization has little to no effect on how the engine vibrates or runs. They would have to be VERY far off to matter at that point.
I agree that at some open throttle position the difference won't matter as much
but it is definitely higher than 3K RPM. On my K7 I could feel the vibes all the way to 5-6K RPM. On the freeway cruising at 75-80MPH with RPMs in that range I could feel vibrations in seat, pegs, handle bars & etc. The mirrors were unusably blurry. Once I sync'd the butterflies those problems went away. As a test I threw in some K9 throttle bodies off ebay with no TB sync adjustment and they worked fine, well within "normal" vibes but I could still feel it. I pulled them and sync'd them per my procedure and the vibrations were noticeably and significantly reduced across the RPM band. Once you taste a properly sync'd TB you can't go back, I swear!
My L4 has the exact same symptoms and I often run it to 6-7K RPM when cruising to reduce the vibes but it does not get rid of the vibrations it only makes them less annoying. Also, if I am running in the twisties then the RPM is varying from 2K to 9K and the vibes are particularly bad. I hate it and my K7 was much smoother.
Since the 650 runs with the throttle a bit more advanced in all conditions, you get past where the synchronization matters quickly compared to the 1000.
I am sure there is a difference in the throttle positions for 650 -vs- 1000 for a given condition primarily due to the higher HP of the 1K (whatever the speed/load on the bike the 1K needs less throttle to hold steady) but I highly doubt the difference is all that much. Moreover, its not like the 650 is under powered and you have to run WOT like a 250 while the 1000 is running with a slightly cracked throttle. The 650 is still susceptible to vibration due to badly sync'd TBs and, as far as I can tell from actual tests, they don't have to be wildly out of balance.
If you are chasing vibrations at speed, TBS isn't usually the cause. A large imbalance can sure cause it, like when a throttle body boot slips off on the 1000's. Anything above idle and low speed, low load operation isn't likely going to be fixed with a TBS. Once the throttle blades open beyond about 1/8 of the way, synchronization just doesn't mean much.
I disagree and I doubt my arguments will convince anyone but if someone has a viby bike and wants to try my procedure I am happy to advise.