Hi Africa, send us some pics showing the top of the cooling head (and the graphics on it), then we can determine what Gen motor you have, and what model carb and crank it has fitted. This is important in terms of rod replacement and tuning etc.
All the motors from Gen 4 onwards are strong, but can be a little tricky to tune if you don't know what low speed needle you have fitted.
We will sort you out and get you on the right track - no worries