classic motorcycle forum

I had a '71 650 Bonnie that was smoking heavily out of the right side.  It was quite some time ago so I am not certain how, but I figured out that the oil pump was not doing a good enough job scavenging excess oil from the sump.  I am thinking maybe I had pulled the sump plug and a lot of oil still came out even after just running it.  I replaced the pump and the smoke was gone.  I kinda hope this is still not your problem as it looks like you have gone through a lot of trouble and expense to come back to where you started!  It could be you have a some restriction or obstruction in the scavenge pipe even.