drive sprocket removed turning now to fig1 there illustrated is a first embodiment of a motorized bicycle 10 of the present invention the motorized bicycle 10 comprises a bicycle type frame assembly 12 which may be modified or of standard construction having a front wheel 14 and rear wheel 16 rotatably secured thereto as is well known to those skilled in the art in accordance with the present invention as seen clearly in fig1 a horizontal shaft internal combustion engine 18 such as those commonly employed in lawnmowers and low powered devices of similar type is secured at one side of a central region of the bicycle type frame assembly 12 where the pedals and sprocket of a standard bicycle would normally be held a motor pulley 20 extends from one side of the internal combustion engine 18 as shown in fig1 and 2 an extension 22 is affixed to or formed concentrically to a rim 23 of the rear wheel 16 of the motorized bicycle 10 this extension extends from the same side of the rim 23 as that from which the motor pulley 20 extends from the side mounted engine 18 a drive belt 24 forms a continuous loop from the motor pulley 20 to the rear wheel rim extension 22 transmitting power from the internal combustion engine 18 to the rear wheel 16 when a clutch pedal 28 is engaged see below causing rotation of the rear wheel and propelling the motorized bicycle 10 laterally in accordance with the principles of the present invention the belt and pulley drive train can be interchangeded with a chain drive train a footrest may be added to the frame 12.