Brake light issue on my TBR7
 

So far, just over 250 of whatever units the odometer reads and aside from learning pains and a tank fuel sensor that barely works, I've had no issues with it. That changed yesterday. It finally warmed up enough outside for a quick ride, so I was doing my usual quick look over before taking off and found an issue. The rear brake no longer activates the brake light. The front brake still does, and i tried messing around with the spring and switch that connects to the rear brake but got nothing.

So aside from that switch being bad what else should i look for? None of the wires i can see just looking under the bike are loose but i haven't taken anything off to get any closer looks. And considering ive been primarily using engine plus rear braking so far, it's a pretty important thing to fix.

Did you pull the post on the switch with pliers to see if the switch works. It may not be getting pulled out far enough (the switch can be adjusted to be farther from the lever to pull the post out further). If the brake light isn't turned on no matter how far out you pull the post (to the end of travel), check the wiring...
disconnect/reconnect the wires to the switch.

Still no good? You can check the switch with a multimeter (ohm meter). You might need a new switch!

How about a new light bulb,worth a try. There cheap ,or could have a bad ground.

Or your multimeter, if you’ve got one.

Gave the pliers a try and it worked. Have it adjusted out to just about the end of its adjustment range and it still only lights when I fully press the brake, so I'm definitely gonna have to figure some other solution cause the spring it came with is clearly no longer working. Thanks for the tip wouldn't have thought to try pliers, tried messing with its adjustment yesterday and pulling with just fingers and got nothing lol. Glad it wasn't something worse though

Shorten the spring by pushing the open end of the spring toward the main part of the spring itself with a small pair of channelocks or needle nose pliers. Bend slowly and you should have what you need adjustment wise. Good luck.

Get rid of that mechanical switch and convert over to a banjo bolt brake switch on the rear master cylinder so it replaces the banjo bolt for the rear brake line (very top fitting). Should be an M10x1.25.
What I use. https://www.amazon.com/Goodridge-Ban.../dp/B000GTV0RC

I remove the old switch, cut off the wires as close to the body of the switch as I can, and solder on an extension for each wire with shrink tube. This way it can plug right into the factory harness. If you want to make it a little easier to swap out in case it ever goes bad use some bullet connectors instead of solder on one end.

The mechanical switches are failure prone and finicky. I installed mine when I first got the bike and never looked back.

Dan's banjo bolt solution is a good long term solution. For now, you can shorten the spring connector. Just bend the hoop part of the spring to make it shorter. So you can have brake light for now. If you bend it too short, readjust the switch position.