Hello, I bought a used motorcycle Piaggio Gilera DNA 125 BJ.2001. Since I don’t know this model before I have a few questions about it. During the test drive I found that the digital speedometer does not work (only the speed). Could that be a cable off. But how do I get the cover to the speedometer off? Is there possibly a workshop book for this model? Who can help me with it? Thank you Frank N.