Hi after struggling for years trying to stretch these belt over the pulley i finally realised it can be easily done by using a medium sized screwdriver and simply levering the belt on by using the top of the motor just insert the screwdriver between the motor shaft and the pulley under the belt and on top of motor and ease the belt on to the pulley simples hope this helps thanks John
or
leave the nearest bolt of the pullry wheel out. leave the other one loose enough so it will unhook and flip over. put the belt on the pulley and use the pulley pivoting on the remaining bolt to stretch the belt till it locks into postion. put the other bolt in and tighten up