Quote:
Originally Posted by HoneyBadgerRy
So after doing some research, I can't find anybody with a four stroke motor who melted a hole in the piston without either having stupid detonation (which caused other problems) or boosting the hell out of it. I should get some kind of trophy for this (I guess I did though, A piston with a hole in it to go with my display).
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Almost a complete hole.....this is from our bike with the Powroll kit. It's a second hand piston we got...crown was way too thin after we looked at it more in depth and it had been machined underneath the dome around the pin bosses creating a weak spot. Didn't find out until it lost power during a race and started missing. I killed it and pulled off the track....just in time before it fully grenaded.
You said there was a lot of carbon on the rest of the piston...running rich can cause this to build up, create a hot spot and cause detonation. Running lean can cause detonation too as well as ignition timing, cam timing and other things.
Although, in this case, I suspect you ran out of coolant, overheated the motor and this is what caused the cylinder temp to rise and detonation to occur.
