Honda CB360T turn signal relay keeps breaking

Hi, my bike is a '75 Honda CB360T.

My turn signals stop working after about 15 minutes or so of riding and using them. I'm running the stock turn signals although I shortened the original posts. When I replace the turn signal relay they work again for a short period of time, then stop working. I've replaced the relay twice now, using the 12v rectangular kind, 1 from Old Bike Barn and 1 from Common Motor.

I believe the turn signals were fine prior to a handle bar switch I had a friend do. He removed the headlight during the process and disconnected all the wiring inside the bucket. Wondering if something was missed during re-connection, like proper grounding or wrong connection, although the blinkers worked for a while after the bar installation so that seems to indicate everything was reconnected properly, but I'm not sure (I'm a first time/just learning/do-it-yourself'er mechanic).

Currently when I switch on the turn signal, it doesn't work and I can feel the relay switch getting warm after about 15 seconds or so. Not sure how significant that is but wanted to mention.

That's about all the history and details I can think of. Any help is greatly appreciated!

Grab a multimeter with an Amp setting and place it inline between the flasher and the gray wire. Signalling in each direction, please let us know how many amps you're pulling.

Thanks for the response. In the meantime I installed an electronic relay and it works. If it stops working after a time I'll do as you suggest to see what kind of power I'm pulling from the battery and go from there. I forgot to mention in my history that I replaced the factory regulator and rectifier with a combo-unit, which I'm guessing may be the root cause of the non-electronic relays failing.

I wouldn't try to guess as to what the problem is until we have more information. Relays are pretty sturdy and can usually take a bit of a beating. If your regulator were bad, it's usually the headlight or tail light that would go out first.

Agreed - if you're pumping much more than 12v through the circuits, your lightbulbs will burn out before the signal relay.

Check voltage at the battery when idling and when revving. At idle it should be around 12v. When revving it should be 13-14v.

What sort of riding are you doing when the relay fails? Around town from stop sign to stop sign, or extended runs at higher revs?

Light bulbs burn out faster because of resistance, not voltage. It's resistance that makes them light up, so too much shortens their life. Poor wiring or connections is often the culprit to short life.