If you want to perform adjustments to your Gilera Coguar 125 then it is usually recommended to have a Workshop Manual to use as a reference in case you want to know the best way to remove a particular component much like the Exhaust and match it again in the correct manner.
Gilera Coguar 125 Workshop Manuals provides specific diagnostic facts with regards to your car so if something is faulty it helps you determine what the problem is and tips to make it better. Then you are able to determine if this can be done on your own or if ever the job is simply too big you could make a booking for your Coguar 125 right into a decent repair garage.
Gilera Coguar 125 manual