This is my favorite!
WM CAP w/Saito .91
I,ve flown this model for 5 years now. Beautifully overpowered, and rock solid.
After 16 gallons of YS 20/20, and 300+ flights the .91 finally gave up the ghost.
lost an exhaust valve retainer. My theary, after seeing some mettalic particles during cleanup is the crank bearing started to fail and particles got into the valve guide. The valve stuck and retainer came off. Cost 82 bucks to rebuild, and runs perfect