It's like a box of chocolates. 50 year old motorcycle. multiple PO's

I melted the piston in my TC185. I was on the highway, holding it at full throttle for about 5 minutes.
When I disassembled the top end, there was no head gasket. Did a PO forget to put it in? Was it intentional, trying to increase compression?
How much compression increase would this provide? Could this have contributed to my melted piston? 
 

This used to be “a thing” back in the day with 2 strokes (lap the head to the barrel with valve grinding paste and delete the gasket 
Also after prolonged WOT you need to “blip” the throttle when slowing (shutting the throttle means no 2 stroke oil being drawn in and overheating the piston)

ckahleer post=917509 userid=54928I melted the piston in my TC185. I was on the highway, holding it at full throttle for about 5 minutes.
When I disassembled the top end, there was no head gasket. Did a PO forget to put it in? Was it intentional, trying to increase compression?
How much compression increase would this provide? Could this have contributed to my melted piston? 

 

Deleting the head gasket may have put the compression up by 1 point and since its low compression anyways it probably did not contribute to that hole.

For example, a .040" gasket on a 70mm piston gives about a -1.5:1 compression difference. It also really depends on the piston dome and combustion chamber volumes, there are online calculators to figure this out.