I don't know why you want to take them out, but FWIW...
I mounted a 550 front wheel + brake disk + sprocket on the back of a friends' 750...with no cush drive...this was last year, before the real brake experts here convinced me that the cush drive was necessary...on my bike...
But the 750 is still out there zooming around somewhere, so it hasn't failed yet...I'm pretty sure, because the OEM 750 wheel is still in my basement, in case the 750 owner needs it...
My misgiving came from being only able to find 6100 series bearings to use with the 550 front hub and larger dia rear axle...