sweetchallenger

OK, figured this out. It turns out to be what we know as the exhaust waterbox rave valve. Although not really a rave valve, its true name is "water pressure regulator."

When working correctly it varies the flow of cooling water into the midpipe according to rpm, sending less at higher rpm. Just snap the metal clip aside and the cap with the red adjuster in the center lifts right off. The valve lifts out easily. Mine was disintegrating and that enabled water to flow around it and gush out from under the cap... big time! Also, it wasn't just high rpm but a combination of heat and rpm that caused it to leak noticeably... something I never saw since I only inspected it it upon starting and warming up while everything was still cold.

Good luck to all.

OK, figured this out. It turns out to be what we know as the exhaust waterbox rave valve. Although not really a rave valve, its true name is "water pressure regulator."

When working correctly it varies the flow of cooling water into the midpipe according to rpm, sending less at higher rpm. Just snap the metal clip aside and the cap with the red adjuster in the center lifts right off. The valve lifts out easily. Mine was disintegrating and that enabled water to flow around it and gush out from under the cap... big time! Also, it wasn't just high rpm but a combination of heat and rpm that caused it to leak noticeably... something I never saw since I only inspected it it upon starting and warming up while everything was still cold.

Good luck to all.

I had a broken rave that looked just like yours. You need not worry. There is a 99.9% likelihood the broken piece(s) are laying innocently at the bottom of your muffler where they're not likely to do any harm. The reason is that the gasses exit the combustion chamber with extreme pressure into the exhaust. The pressure that helped the piece of rave valve break off likely aso carried it away. Good luck!