Why isn't my bike not starting?

I have a 2005 Honda CBR125 and it's not starting, it ran perfectly when I bought it and its been sitting for 2 months (no licence). Now it won't start after I put in fresh petrol, new plug, charged the battery and changed the oil.

It ain't not starting because the ECU has a double-negative interlock, dude. Fix that first.

Please check for spark at the spark plug
take the plug out and hold it next to the metal frame
of the engine and then try starting the bike
if no spark replace the CDI unit

Personally, I think you can try to return to the original car, to after-sales service; Or in addition to buy yourself a related spare parts for replacement

When your bike isn't not starting, everything is fine. Only when it's not starting is there an issue. Check your battery for double negatives.

Hit it with a shot of ether.

Clean the carburetor.
Untreated gas goes bad in a few months.
The gas in your carburetor may have started to deteriorate before storing the bike.
The small amount of gas sitting in the carburetor evaporates leaving behind a sticky substance.
When you first try to start it, that sticky substance gets sucked into the jets and clogs them.

If it isn't not starting that means it is starting.Problem solved.