First, a word about octane ratings.
"Octane" can mean several things depending on your locale. In most of the world, it refers to RON (Research Octane Number) which is a standardized test for combustibility. There also exists a Motor Octane Number, or MON, which attempts to estimate combustibility in practical settings. The standard used in the United States is an average of the two numbers, which you may have seen referred to as (R+M)/2, or simply "octane."
What this means to us:
Piaggio recommends using 95 RON or greater. This roughly equates to 91 (R+M)/2 octane, which so happens to be the "premium" fuel available at most stations. This is the minimum that should be used on a regular basis. Note that regular 'unleaded' in the UK has a rating of 95 RON.
The reason 91+ is recommended is that lower grades can lead to detonation or pre-ignition when used in high-compression engines such as our scooters'. However, detonation (or "knock") is more of a long-term problem than a short-term one. So, if you're stuck in the middle of nowhere and all you can get is regular, a tank or two of the cheap stuff won't cause any serious damage. If detonation were occurring in your engine, you would hear and feel it. Detonation can lead to pre-ignition which in most cases will cause damage to the spark plug, piston top and top ring.
Last Updated Mon Sep 26, 2011 6:40 am