Altitude can affect engine performance due to the decrease in air density at higher elevations, which can result in reduced power output. However, modern motorcycles are designed to compensate for these changes and can generally handle altitudes without significant issues.
It's worth noting that factors such as the rider's weight, cargo, and road conditions can also influence the motorcycle's performance. If you're planning to travel at higher altitudes or in mountainous regions, it's a good idea to ensure your motorcycle is properly maintained, and you may need to adjust your riding style to account for the change in conditions.
For accurate and specific information about your Aprilia Storm 125 BS4 and its performance at different altitudes, I recommend consulting the motorcycle's user manual or reaching out to the manufacturer or an authorized dealership. They will have the most up-to-date information and can provide guidance based on the specifications of your particular model.