Just pulled mine to decide if I needed to pull the motor apart. Seemed to run fine, but I guess I'm pulling it apart to replace the chain guides! It's an 81' with 34,000 miles on it and the sump screen was completely blown out, no surprise! I wonder if the filter was ever replaced. I also found a little spring looking thing in the sump. Looks like one of the springs that goes around the back of a shaft seal to maintain tension on it. Also found a small washer in the sump. Not sure where that came from. Every bolt on this bike is rounded off, so I think there has been some motor work at some point, hopefully it just got dropped in there.
Greg