NOTE: DO NOT USE UNLEADED GASOLINE
NOTE: DO NOT USE UNLEADED GASOLINE is a warning on older mopeds and in older moped owners manuals. This warning can be ignored. The purpose of this warning was to prevent people from using white gas in mopeds, and it does not refer to unleaded gasoline as we know it today. Two-stroke engines do not require, and have never required leaded gasoline.
These warning stickers are commonly found on Puch mopeds. And also found in other moped manuals.
"In general, two-stroke cycle will operate without problems on unleaded gasoline. These engines do not have valves, and most will actually benefit from using unleaded gasoline because of reductions in spark plug and combustion chamber deposits. Lead is not required to provide lubrication for pistons or piston rings, as is sometimes claimed. Owner's manual recommendations should be followed, particularly for new engines under warranty. Owners of older engines should contact the manufacturer for guidance in choosing a proper octane fuel, or to obtain service information about ignition timing and low compression kits which may be required for unleaded/low lead fuels of lower octane.
In discussion with Briggs and Stratton, a major manufacturer of small engines for lawnmowers, pumps, etc., they indicate that all post-1979 engines can use unleaded gasoline and that they do not anticipate any problems with pre-1979 engines for normal service."