You start up the motor to realize you forgot to install an o-ring in the oil passage..
Yup... Put some new rings in the elefant, spent all day saturday getting the motor reinstalled. Started it up and then saw the oil spewing from the head and barrel interface.....
But good news was, I was able to re-pull the motor, open the offending cylinder, rectify the situation and get the motor back in the bike; then have the bike running in under 3.5 hours.
Moral of the story: When you’re friends drop by to pack a bowl while you’re reinstalling your cylinders late at night... double check your shit.