Used OEM Yamaha SBN 44mm carb from a 1990 650 Super Jet. This is the early style SBN carb. It WILL need a good cleaning, and fuel re-build. ALL screws turn. Current jetting specs = 2.5 needle and seat, 65 gram spring, 115 low, 125 main jet. We also sell genuine Mikuni carb kits, needle and seats, and complete jetting kits if needed. Please email with questions before ordering, NO returns on any used parts, thank you.