I have experience with the WSM carb kit and mikuni carb kit I compared them both in person and the WSM regulator diaphragm while it looks like the OEM one from a far (due to the red knob) it does not feel like OEM material in flexibility or quality. I also found the WSM kits to have very low quality fuel pump check valve gromets they were junk, rest of the kit is ok but I didn't use my WSM kits for fear of issues.