Prep jars and lids. Wash jars, lids, and rings in hot, soapy water. Rinse well. Place jars in water bath canner or a large pot of hot water or in the oven while you prep the fruit. The jars do not need to be sterilized, but they need to be hot and clean. Keep everything hot until you're ready to use.
Prep pears. Fill a large bowl with water and a bit of lemon juice to prevent browning. Wash pears well. Peel, core, and slice pears into halves or quarters. Place cut pears into the bowl with lemon water to keep them from browning while you work.
Make syrup. In a large pot, mix 2 cups of sugar with 8 cups of water. Bring to a boil, stirring until sugar is dissolved.
Pack jars. Drain pears from the lemon water. Use a jar lifter to take a jar out of the hot water. Place on a towel. Use a canning funnel and ladle to pack pears into jars. Pour the hot syrup over the pears, leaving ½-inch space at the top.
Put on lids. Wipe the rim of the jar with a clean towel. Place a new lid on the jar. Screw on the ring until fingertip-tight.
Process. Put the filled jars back into the water bath canner (or large pot of boiling water), making sure they are covered by at least 1 inch of water. Boil for 25 minutes for quart jars, or 20 minutes for pint jars. Use a jar lifter to remove jars from water. Place on a towel.
Cool and store. Let the jars cool. You may hear a popping sound as the lids seal. Once the jars are cool, check to make sure the lids have sealed by pressing down in the center of each lid. If it doesn't pop back, it's sealed. Store jars in a cool, dark place for up to a year.