Buy some Sta-bil fuel stabilizer & a gallon of 92 octane fuel, add the correct amount of Sta-bil for 1 gallon of gas. Then drain all your fuel out of your tank, then run engine till it dies. Then install the new fuel with sta-bil & then run engine for 10minutes.
Shut the fuel off at the carb, run it dry, the drain the tank. Remove the cap place a plastic bag or similar under the cap
and and tighten it down. This prevents expansion and contraction from pulling moisture into the tank. It will sit indefinitely like that.
For winter storage I drain the tank. Then run it till they stop. I then remove the spark plug and put the cylinder at bottom of the stroke and fill the cylinder with Sea Foam, then put the plug back in. On 4 strokes I also drain out all of the oil and fill the crankcase with Sea Foam. When you're ready to use the engine again remove the Sea Foam and put in 100% ethanol-free gas. On the 4 strokes drain the Sea Foam out of the Crankcase and put in oil.
Shut the fuel off at the carb, run it dry, the drain the tank. Remove the cap place a plastic bag or similar under the cap
and and tighten it down. This prevents expansion and contraction from pulling moisture into the tank. It will sit indefinitely like that.
Yeppers, if sitting more than 2 months empty the tank and run the carb dry. With a rear FD just holding the bike up on one wheel it's easy to empty the tank out.
Here's the factory recommended procedure: (for 4 strokes)
1. Siphone all the gas from the gas tank
2. Start the engine and run it until the engine stops, and all the gas in the carb is gone
3. Remove the spark plug.
4. Add about 5 cc's or 5-10ml of 30 wt oil to the engine throught spark plug hole.
5. If a 4 stroke pull the starter rope 5-10 times to distribute the oil in the motor.
6. Re-install the spark plug.
7. Pull the starter rope until you feel resistance, to close the valves.
8. You're finished. Store at any temp.
I do this and my snowblower and lawnmower usually start with one pull
after storage for 9 months in cold weather.