In testing for vacuum leaks today, I noticed that if i spray the bottom of each cylinder base just above the push rod tube seals, the idle will drop. If I spray enough, I can make the engine die. Spraying the typical intake tract culprits ( elbow rubbers, intake spigot, end of butterfly shaft, etc) yields no change in idle. I'm guessing that the spray is entering the crankcase and being passed through the breather to to the carbs, but I don't have oil leaking at the cylinder bases, and have just completed a re-torque and valve adjustment. The pushrod tube seals are weeping, but not dripping.
The sump pressure created by 2 pistons coming together would surely push out oil if there was any type opening. I think you only have a happy coincidence.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
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