The problem is, I want to be able to swap back and forth between dirt and sumo, and modifying the 150f swinger will eliminate using the stock rear wheel/brake system. I suppose I could buy a spare 150rb wheel, or a spare 150f swingarm to keep the knobby wheel and drum brake on it. In any case, the 150rb swingarm will not work with the 150f shock location, so that will be going up for sale for sure.
Also, the 150r sprockets are 420, and have a 4 bolt pattern, whereas the 150f has a 520 pitch, and a 6 bolt pattern. Does someone make 520 sprockets for the 150r?