Are the unpainted aluminum engines lacquer-coated to prevent corrosion? Or painted with silver paint? They don't seem to corrode like bare aluminum would.
My DLX engine is painted silver. Changed the oil the other day and flakes of silver paint came off the crankcase lug that protects the oil drain plug.
Note I'm talking about the cast engine block here, not the stamped parts which are usually lacquer coated on bikes. After watching some videos of other bike engine restorations I'm beginning to believe these engines have no paint or lacquer on them; they're "raw".
The lug that had the silver paint flake off is part of the engine case casting. The paint flakes look like the rest of the engine including the cylinder fins. So my engine is painted silver except for the polished and clear coated side covers.
Thanks, that's interesting.