BMW engine is not required....but the engine allows for a very low racing outfit, makes for faster cornering.....
I should note that sidecar racing makes it a lot more fun for the driver, due to the fact if he makes a error/mistake on the track he can blame his racing passenger....However, that did not work for me when I was competing because my passenger was my wife Linda....................................................................
Bones, if I get it completed in time for Miller your welcome for a ride.....................................................