If you choose to carry out adjustments to your Hercules K 125 S then it is usually recommended to have access to a Workshop Manual to keep just for a guide if you need to know the right way to take out a particular component like the Wheel Bearing and install it again successfully.
Hercules K 125 S Workshop Manuals offers clear exact diagnostic info for your car therefore if something is broken it will help you discover what the problem is and the best way to correct it. You can then evaluate if this can be done by yourself or if the job is too big you can actually book your K 125 S in with a nearby garage.
Hercules K 125 S manual