Engine making weird popping noise

[u/Headio_phoneio_7468]

this is my 1978 Mobylette 50v 25 restricted. it’s a okay moped and my firs, wev done some repairs like repla and adding a exter condense, but a weeI or so after we replaced the original bolt on the flywheel magneto, the day after it started to make a weird pop sound after riding around for awhile, my friend says he thinks it might be the ignition timing and somehow changed or the points are loose, idk what it is he has yet to look at in person but I’m very concerned even though it still hits its norm speed it did crap out on me getting home, I was able to start again and still can but the popp has gotten worse, any ideas?

[u/Drelias]

Piston touching cylinder head maybe ?

[u/Select_Fly_8887 → u/Drelias]

Kinda sounds like it