Needle bearings aren't tapered. Needle bearings are a type of roller bearing where the rollers are very long compared to the diameter of the rollers. Most 2 stroke gasoline engines use needle bearings on both ends of the connecting rod so they don't need a large amount of oil in the fuel to lubricate the bearings. Glow fuel engines use bronze bushings in the connecting rod and require 15-20% oil. Most gas engines can get by with 2-3% oil.