>What is the general thought on aircooled 1600's and synthetic oil?

The consensus is that if you ask this question you are going to get an
avalanche of anecdotes and baseless opinions with no facts whatsoever. To
wit:  ;)

1. It is stupid to use synthetic in an engine with no oil filter. It's
stupid to chuck the expensive stuff after 3000 miles, and you'll still have
to, because it will be just as full of dirt and glitter as conventional.

2. If you do ream your 1600 out to accomodate a filter,

   a. It will make your engine leak if its seals are already used to
conventional oil.

   b. It will not save you from mechanical sloth. I have used synthetic
from new and still thrown a rod within a few thousand miles. Sloppy FLAPS
rebuild. Spend your money on wrenches and your time on knowledge if you
must make the choice, and do the hardware yourself. Synthetic is a good
lubricant but it is not a magical potion.

3. Synthetic might buy you an inch, but good maintenance will buy you a
mile. The former costs money where the latter takes time. Spend the time.
Frequent oil changes are a pain in the neck and valve adjustments will
bloody your knuckles, but it's the right way.

--Ken
  68 Westy, 71 Bus