Electrical shenanigans

Hi guys
Having a problem with my CB500 at the minute, the tail light doesnt work, but the brake light does when the brake is pressed. If you turn the lights on the brake light comes on permanently, which strikes me as odd (surely it should be the same regardless of the switch position). I've also noticed the bike struggles to start with the headlights on, but it's a brand new battery, was figuring it could be switch or ignition but didn't know if anyone else has come across this? Thanks

Sounds like your brake light switch is faultly...(is it front brake light switch).... also regulator rectifiers can be faulty..(hard to start)... also there two filiments in rear brake light bulb... (so check ones not blown)

It would certainly be worth checking the type of bulb that is the rear brake light - it should be one of the dual filament stop and tail bulbs - if someone has put in a single filament bulb (assuming they could get it to fit!) then things won't work well...