If that has already happened the fix is to send it back to BME. It will cost some dough but the top end will be replaced or properly repaired. What happens is the pistons get so hot they leave aluminum trails on the cylinder walls.

Indications are low compression and lost peak rpm, seemingly erratic carb settings, and frequent stopping in flight. Makes for a very unreliable engine. There is a home fix if the damage is relatively minor but it is at best a temporary one. That's to remove the cylinders, look for traces of aluminum on the cylinder walls, and use muriatic acid (pool acid) to clean the aluminum off the cylinder walls. The cylinder must be removed for this. The acid will kill a piston real quick. Also clean out the ring lands of the piston with a suitable tool. A burned side on the piston is another indication that you killed it, and probably also have a stuck ring. I met a 115 this past weekend where it has already been toasted. Owner stated that (paraphrased) it got so hot the coating on the cylinders was burned off. Baffles and mixture again.

Not much acid, use a compatible brush, wear a mask, eye protection, chemical apron, elbow length rubber gloves, and have an acid neutralizer and chemical eye wash right handy should you spill or splash any on your person. If you think I'm trying to scare you away from doing it, you're right. Better to send it back. The bottom end is likely still good and the cylinders may be salvageble in the right hands.