I have not seen that style flat slide Mikuni before, but it looks like it is an oem fitment for something. It looks like a nice piece. The oem Ascot carb is a cv and they generally flow less than a comparably sized slide needle carb of the same slide configuration. For example, the XL500s uses a 32mm round slide carb compared the the 35 CV. I stll think it work fine on a stock motor with a free flowing exhaust. If you ran a mild cam and a 10.5 : 1 piston you would have a real nice package.