Sure with the decline of 2-stroke powered ATVs, you don't hear much about the reed valve but one reader wants to know why the petals aren't made out of something that can last forever... like metal:

Ask the Editors: A Stronger Reed Valve - ATVConnection.com

 

When I read the title of this thread the first thing that came to mind was metal fatigue. If you keep bending metal it eventually cracks and breaks.

 

They were made of metal...but metal, like anything else, doesn't last forever and will fatigue (crack) when flexed enough times. Resigns & such are used today because they are less likely to bend & stay bent and allow some level of tunability...

 

Best place for metal was on the old rotary valve engines on the early Kawasaki,Suzuki type engines. Actually no force on the metal,just uncovered an opening for the fuel air mixture to enter the cylinder. Precursor to the modern reed valve systems. Many are still out there in rc engines that can exceed 22,000 rpms or more.No fiberglass or any other reed could take that much pressure. Talk is that was where Rotax originally got it's name. Don't know if it's true or not.

 

I remember metal reed valves.. Usually they splintered before snapping off, but not always. Sure did mess with things when they did break off. I also remember wondering why they were made of metal.