Drag Specialties Replacement Pistons For Harley Twin Cam With 103 Motor Drag offers this piston kit as an easy and economical way to replace your pistons. Features: 9.6:1 compression ratio 3.875 bore For 103 motors OEM quality cast aluminum alloy construction Coating that extends piston life, reduces friction and allows for cooler running engines Ideal for OEM replacement Economical with great performance Kit includes two pistons with wrist pins and clips Accepts OEM or Hastings rings (sold separately) Note: Rings not included (sold separately).