Im close to buy a bike and for the same price Im between a CB750SC 83 and a CB900F Boldor 81. The first one has less CCs (and HPs) and maybe it could be mor hard to find spare parts, but its much more beauty and I love the 4 to 4 exhaust tubes. But, moreover than the appearance of that 4:4 tubes I think could be possible to regulate the carbs not measuring and compensating vacuum from inside of the carbs but doing it individually, carb by carb, by measuring the correspondng gas exhaust composition with a home made lambda prove. You could buy one or there are some web pages explaining how to make it by yourself.