The battery on my 125cc motorbike isn't powerful enough for any extras. Can I use a jump starter power bank and wire some extra LED lights directly to it as you would to the main battery?
A few caveats. Ensure the lights you are powering are 12v ready (assuming the jumper pack is 12v as well). Then you just need to worry about two things.
First, where to safely house/keep the battery while the bike is in use. You want to ensure the leads coming off the battery pack do not come in contact with anything metal on the bike. If they do, plenty of sparks could erupt. This could also kill the electronics on the bike itself. Just be extra cautious.
Secondly, you'd need to charge the battery pack daily to ensure your lights never cease functioning.