It's not the baffle causing the grey gunk.

I've seen it on dozens of Evolution engines including a half dozen I own myself.

I've used baffleless Pitts style, and other muffler setups on brand new Evolution engines and all do the same thing.

Check out Greybeard's post as well.

If you pull the backplate on a relatively new engine, you'll see the wear the crankshaft produces on the backplate.

You'll also often see the same particulates on the inside of the engine, which are not being blown in by the muffler.

It is these particulates that make up the goo.

The baffle plate is made of a different material than the engine shell itself.


If you want reproduceable empirical evidence:

Burn a bit of the goo after cleaning in distilled water, and you'll see it's characteristic combustion color.

Burn a shaving or scraped bits from the engine shell, and you'll get the same color.

Burn a shaving from the baffle, and you'll get a different color.



You can remove the baffle on a brand new engine, and it still produces the gray goo in the same amounts.

I've done this too.