It's important to pick one oil and stick with it.
Most Italian scooters both new and old are powered by what is known as a 2 stroke motor. This type of motor differs in many ways from that of the 4 stroke in a car. One of the differences is how they are lubricated. Four stroke motors are lubricated by an oil bath covering all the motor's moving parts. Two strokes, on the other hand, receive their lubrication from oil which is mixed with the gas that the motor is burning.
When the 2 stroke motors first became popular 50 years ago they were designed to burn huge quantities of oil, 8 to 10 oz. per gallon in most cases, mixed directly with the gas. Modern day motors can burn as little as 1 oz. per gallon, with many of them having pumps delivering the oil directly to the engines main bearings.
Modern-day 2 stroke oils are very advanced and designed specifically for certain applications and uses. There are many different grades and types of oil you can burn in your 2 stroke scooter, but which one or what type should you use?
First and foremost, be sure you are using 2 stroke oil and not motor oil. Next, make sure you are using a 2 stoke oil that is specifically designed for a motor cycle, not oil that is meant to be used in your neighbor's chainsaw or lawn mower. The last thing to keep in mind is to pick one specific oil and stay with it. Many modern oils build up a lubricating film over time. Constantly changing oils or brands will keep this from happening.
Big People Scooters carries 2 brands of oil. Bell Ray, a very high quality, U.S. made oil which is readily a available brand. And Motul, a French oil brand that specializes in low smoke synthetic oils. It's a little harder to find if you are on a road trip. We have been using these oils in both our street and race scooters for over 10 years and are very happy with the results.
If you have a newly re-built or tuned motor then you should definitely burn a synthetic oil, Motul 200 or Bellray SI-7. They cost a little more, but the lubrication is superior and they burn much cleaner, leaving less deposits in your motor. Standard mineral oils, like Bellray S-2, work very well. If you are planing on de-carbonizing your motor regularly, or a rebuild is in your future, it is a great oil at a economic price.
Synthetic oil can be made to match the specific requirements of certain applications. Motul T200 is a low smoke oil that can be used in both pre-mix (added to your gas when you fill up) or injector (mixed automatically for you by your scooter). Motul 600 and 800 are top-of-the-line race oils that are designed for high revving, high compression tuned motors. T200 is made specifically for pre-mix racing applications.
When you switch to a synthetic oil you should drain your oil tank if you have a injector bike - run your bike low on fuel if you are pre-mix - then start using the new oil. Be light on the throttle for the first tank so you can build up a film, but remember to stay with the same brand after you make the switch.