OK I KNOW that frame kit. It is a very well made unit and will make your job much easier.
The slight smoking on start up is probably caused by the valves. The f2/3 bikes had a different stye valve train and unless redone with new parts, were prone to premature wear.
That frame kit will allow you to remove the head with the engine STILL in the bike, something normally impossible on the sohc 750 unless you had the A bike.
Otherwise that is a very nice bike. What was the name of the guy you bought it from? First is good enough. I wonder if I know him.
The ride IS the adventure. The destination is just to get gas!