I disagree with the location that MEngr gave you. The S/N will be stamped in the frame on the right hand side directly beside the battery box. You'll need to scrape to find it though. The serial number sequence he gave is correct. Happy Hunting! On the oil leak, the Continental engines have rope seals for the front and rear mains. If the seal gets hard, as it does over time, and you have a little play in the crank shaft it'll allow oil to seek past the seals. Very common ocurrance.