My 49cc Huasheng 4-stroke had gotten gradually more difficult to start, and the top end was down by about 10 MPH -- really dogging it. Then it occurred to me that I've been refueling my bike from the same 5-gallon gas can that I filled up many months ago. The way these little engines sip gas, I very infrequently need to fill the little 1.5-liter tank. Plus, the bike and the gas can are stored in an unventilated shed, so the gas has seen some very high temperatures because of the above-average heat that we've been having this spring and summer. I feel like an idiot for not sooner making the connection between stale gas and my performance decrease! But I'll only be filling my tank at a gas station from now on. With the fresh gas that I put in the tank this morning, the bike feels about 150% of what it was yesterday. I learned just how stale my old gas was when I removed the fuel line from the carb and spilled gas on my hand before draining it into the 5-gallon gas can. Any time that I've gotten gasoline on my hands before this, the smell was extremely strong and hard to wash off. This time, I almost felt like I didn't need to wash my hands! What a great illustration of the stale gas situation that was. In addition to only filling up with fresh gas at the pump, I also want to start using gas stabilizer. With the 10% ethanol gasoline mix that we get around here, I think that's important. Does anybody have suggestions on a brand of stabilizer? And a mix ratio? Thanks.