So, when I put my AV10 together, the carb was popping out right next to the pedal sprocket. Before the motor could variate much, the carb would hit the sprocket and stop it. I cut down the sprocket to about 1 inch from the crank, drilled some holes in the nubs, and bolted on a bicycle sprocket. no more clearance issues, hooray! on a side note, the doppler pipe is the size of a well built man's thigh. we made pedal pegs, oh so classy.