Halve papayas; scoop out and discard seeds. Peel and cut up papayas; place pieces in a food processor. Cover and process until smooth.
Transfer pureed payaya to a medium heavy saucepan. Add vinegar and both chile peppers. Bring to boiling, stirring constantly. Reduce heat; simmer, covered, 5 minutes, stirring occasionally. Strain mixture through a sieve, pressing with the back of a spoon to remove all the liquid; discard pulp. Measure 3 cups liquid.
In a 6-quart heavy pot combine the 3 cups liquid and the sugar. Bring to boiling over medium heat, stirring to dissolve sugar. Quickly stir in pectin. Bring to a full rolling boil, stirring constantly. Boil hard 1 minute, stirring constantly. Remove from heat. Quickly skim off foam with a metal spoon.
Ladle hot jelly into hot, sterilized half-pint canning jars, leaving a 1/4-inch headspace. Wipe jar rims; adjust lids and screw bands.
Process filled jars in a boiling-water canner 5 minutes (start timing when water returns to boiling). Remove jars from canner; cool on wire racks.