I do worry about that Sten, But I worry about everything .3 mm will be good But I would try to get it supported in the crankcase mouth.
I am surprised that the previous owner of your crankcase was able to open it up to 100 mm. I thought you risked breaking into the cyl. studs threads... Unless the studs were moved.
Cheers... Sten
But as I said to Greg, There is a gap all the way round on a "D",
Not like the older Bikes, "B" and "C",
So how does the engine know how big a gap ?,
I am thinking the liner could crack with vibration ?,
But with the standard liner in my hand , It feels heavy / strong ish ?, At 3 mm
I need a man with a van to follow me !, When I give it some stick .
The only stud that is ground away a bit is a small one that goes across at the front,
About 2 or 3 inches below the top.