Using brand new motorbike engine oil in an old bike should not cause any damage to the engine itself, as long as the oil is compatible with the bike's specifications and requirements. In fact, using fresh oil can actually benefit the engine by providing better lubrication and protection.
Check the owner's manual or consult with a professional mechanic to determine the appropriate oil viscosity and specifications for your specific bike model.
Oil Additives: Some newer oils may contain additives or detergents that could potentially loosen accumulated sludge or deposits in the engine. If your older bike has a significant buildup of sludge or deposits, switching to a new oil may dislodge them and potentially cause clogs or blockages in the oil passages. In such cases, it might be advisable to use an oil specifically formulated for older or high-mileage engines.
Maintenance History: If the bike has been consistently maintained and the oil changed regularly, the likelihood of encountering any issues when switching to new oil is lower. However, if the bike has been neglected or the oil hasn't been changed for an extended period, it might be prudent to consult with a mechanic before making the switch.
Overall, using new motorbike engine oil in an old bike is generally safe and can provide improved performance and protection. However, it's always a good idea to consult with a professional mechanic or refer to the manufacturer's recommendations for your specific motorcycle model to ensure you're using the most suitable oil for your bike.