Hi,David.Welcome to the funny farm!
I totally agree with you about mounting the motor to the bike as close to the center line of the motor.
May I add that the motor should be mounted as far down in the "V" as possible.
I also agree that the only way to completely stop a 2 cycle motor from vibrating is to shut it off.
"That said" I also think that there is alot of room for improvement in minumimizing the vibrations of these motorized bikes.
I am working on a safe way to isolate the motor from the frame if it works great!!
If not "nothing ventured nothing gained"
I have listened to"experts" all my life and many of them I have whole heartedly agreed with!
I have also listened to "experts" and have had to Bite my tounge till it blead before I could prove them wrong.
The motor isn't the only source of vibrations.
I noticed "that" when I installed a sprocket on my first spring-loaded chain tensioner.
Another source is the exhaust,if you have a stock exhaust rev your engine and look at the end of the muffler!
That is why some kits supply that cheezy muffler to frame bracket!
That is why I build my own exhaust and mount the muffler in the back of the bike with a flex pipe between the header and the muffler some of the "experts" think it's the same as a POO-POO pipe
That just shows that they don't know what they are talking about as the flex pipe minimizes the vibrations in the exhaust,and in my opinion it looks"Cool"
Expansion Chambers increases the vibrations good for performance, bad if you are striving for smooth!
I'm also working on that!
I put the "Pundants" and the "Experts" in the same category as the nay sayers that told the first guy
that put a motor on a bicycle that it wouldn't work.
I can see that guy blowing buy the nay sayers peddeling away giving them a one finger salute as he proved them all wrong,and the motorcycle was invented."CAN I GET AN AMEN" Kip.