What engines will fit a 1989 YZ 250 frame?

A 1989 YZ 250 frame is primarily designed for 250cc two-stroke engines from the Yamaha lineup, specifically from the YZ series. Engines from the 1988-1994 YZ 250 models are direct fits due to similar mounting points and configurations. Additionally, some riders have successfully fitted engines from other brands or models, but this typically requires custom modifications. Always consider compatibility with the frame and necessary adjustments for air intake, exhaust, and electronics.