'75 1800 cc. pancake with Syntehtic oil?

Hello,

Firstly, thanks for previous info offered on other subjects recently!
They have been most helpful.

I am wondering if putting full synthetic oil in the 1800cc aircooled
bus will cause any problems with the old type eengine seals. It runs
nicely now, and doesnt use oil, (dripping, or burning). I just wouldnt
want to disturb it, and cause problems if it doesnt like it.

Thanks again,

Bill