The inside of the boot cavity on top has a threaded spike that would ordinarily screw into the end of the lead.
As long as that spike is still inside the top of the boot the lead can be pushed / screwed back into the top of the boot.
If that spike broke off and is stuck inside the end of the lead, or is missing from either location, then a different problem. Then a replacement boot would probably be necessary.
They are stupid expensive new from Yamaha, so finding a used coil with leads and boots would be the next best bet. Occasionally someone who has done a stick coil conversion may have the left-over coils / leads / boots in their spare parts pile.
You might put your scooter model in your profile to make it easier for others to provide assistance when needed.
