question about 49cc cylinder head.

I just pulled apart my 49cc cylinder head, and there is a notch in the cylinder wall just above the exhaust port. I was wondering if this is suppose to be there or it is damaged? Looks like it could be a transfer slot to the exhaust port but wanted to make sure before i put it back together. its a notch the runs straight up from the exhaust port about 1 inch. Anyone got a spare cylinder head layin around they can take a look at and tell me if this is normal or not. Thanks!

Thats a relief notch and supposed to be there............

thanks! I actually pulled apart another motor and found out that had the same notch.

I have the notch in most of my cylinders.
The one without the notch seems to have way more compression.
I dont know if the notch creates more power because its allowing the intake and exhaust gases separate more than if there was not a notch even though theres a lower compression?

Anyone know which one creates more power? notch vs non-notch motor?

Lets see a pic of that cylinder without the notch?

Heres a pic of the inside.
The cylinder looks the same on the outside as any other X1 cylinder.

You know I've worked on a few hundred of these cylinders and never came across any without the notch or even ever heard about any without it. How much more compression do you think it has? or is it harder to use the pull start?