So the OEM drum brake cylinder is stupid expensive, but I just test fitted a Dorman made for Suzuki ATVs, and it's almost a perfect fit. The 2 mounting bolt holes are just a little off, but nothing that can't be handled by oblonging the holes in the drum back plate. And for <$11, it's worth it. Dorman W37850 Drum Brake Wheel Cylinder https://www.amazon.com/dp/B001PYV1I0/ref=cm_sw_r_cp_apa_i_TL5UDbWR61Q68