Dont turn the engine over too much. The grit may be very tiny and you wont even feel it. Do like opJose said, just add an intermediate step.

1) Clean the engine externally with a brush first to get rid of external grit.

2) Then take off the backplate and the carb: easy enough to do that. Dont take off the head yet. Now check in both if there is any grit. If there is none, chances are you goy away without any internal grit.

3) If everything is OK, take the glow plug off and immerse for a couple of days in plain methanol. Methanol will slowly remove any dirt and also any gunking

4) After a couple of days turn the crank over slowly first and then with some speed if every thing is OK to rinse out any grit from the cylinder

5) Take the engine out and rinse under running water. At this time there is no lubrication so be careful.

6) Dry completely and oil thoroughly with light machine oil. Then assemble

Ideally you should do these steps in combination with what opJose has suggested. I am not suggesting to open the head as that will spoil the gasket. I have lost a 55AX that way. Avoid it but if your engine has grit inside go ahead and open it.

Ameyam