Well, i came across this Bonanza MX add and was Floored by this add when it said they were up against minibikes with 30 HP 
. You can see in the ad there is are Rupp right on the butt of that Bonanza MX1510. So my question does anyone know what they did to some of these other bikes to get the so called 30hp or lets say event 20hp out of a 5 hp tecumseh back in the day. Also does anyone have any good old story's to tell about vintage minicross racing or have one of these factory built racers.
. You can see in the ad there is are Rupp right on the butt of that Bonanza MX1510. So my question does anyone know what they did to some of these other bikes to get the so called 30hp or lets say event 20hp out of a 5 hp tecumseh back in the day. Also does anyone have any good old story's to tell about vintage minicross racing or have one of these factory built racers. 
