If you wish to undertake auto repairs on your Yamaha TT R 90 then it is always a good idea to have access to a Workshop Manual for reference should you need to know the best way to take out a certain part for example, the Exhaust and fit it again in the right way.
Yamaha TT R 90 Workshop Manuals gives you identifiable diagnostic details for the car so if something is faulty it can help you determine what the problem is and tips on how to correct it. Then you are able to analyse if this can be achieved by yourself or if the job is simply too big you could make a reservation for your TT R 90 in to a trusted repair garage.
Yamaha TT R 90 manual