I had an amt 450 in my fry beagle f18. it hit the ground with authority. the fire burned everything. The engine was beat up pretty bad. 2 large dents in the case where the gear were shoved into it. I tossed it under the workbench figuring it was toast. About a year later, I pulled it out again. It would not spin freely but it would move a little. I took it to a friends house for wednesday night build night, my favorite night of the week. We took the outer can off and it spun free as can be. We took turns banging out the dents in the can until you could hardly tell anything happened. (Big Thanks to Glenn Sheppard). Put it back together and it still spun perfectly. Searched around and found an ecu, pump etc. Test ran the motor several times and it ran as good as it ever did. I'm not sure the newer, lighter motors would have faired as well. Those amt motors are tough as nails.