Considering the factors you mentioned, such as a 3 HP Tecumseh engine, new paint job, max torque clutch, roller chain, brake cable lever, and carburetor, it is possible that the Alexander Reynolds mini bike could be worth around $250. However, this estimation is subjective and depends on the overall condition and functionality of the mini bike. It is recommended to have it assessed by a mechanic or check listings of similar mini bikes for sale to get a more accurate valuation.