anyone open a 40mm stroke motor after running a few hundred miles?

[crassius]

took one apart and found that either the guy had assembled with only one base gasket or the two gaskets had melded into one

not sure they can do that, but I couldn't find any kind of seam or anything to show the gasket had originally been in two parts

after he had worked on it, the top end blew out - thinking maybe he left one gasket out, but not sure

 

[Frankenstein]

I've seen these odd stacks of paper that was used on a couple engines, certainly if they were left long enough they would bind themselves together like how old books glue their pages together after they get wet.

Maybe measure it, if it's roughly half the thickness in the pressed part than it should be them maybe..

Do you think the single gasket could explode a top end?

 

[crassius]

not sure - never ran one at speed with only the one gasket - I suppose piston could hit head a bit, maybe enough to pinch ring lands

I believe his problem was leaving some rough spots on walls after modding the ports, but cylinder was cracked and broken badly after it failed so no way to tell.

gaskets on these are the tan colored stiff ones with waffle pattern - when putting motor together, I always oil them to be sure of a good seal

 

[gary55]

Most of the 40mm stroke engines until as of late only used 1 base gasket. they used the 85mm rod with a A type piston and a 70.5mm cyl. Zeda's are using a 89mm rod with a B type piston 2 base gaskets and a 69.5mm cyl.