Topic: Brake light non existant/ tail light fine/ no brake light switch on brake lever

[jordanp]

Another most likely retarded question from a newbie cb750k rider.

So far on my bike I know the carbs were off another bike, as well as the handlebars , and some other bits. The brake light has never worked for me... in fact when the brake light switch under the lever was activated it killed the tail light all together. The master cylinder was way blown out, and I found a guy in sacramento that I have been buying parts from( caliper, coils, and now a new master) so the new master cylinder is off a 77, and it has no brake light switch... is this correct? am I retarded or did these bikes not have a brake light?? probably the first one. I just don't know what parts on this bike are actually from this bike!!!!

[mgbgt89]

On my 72 350 the brake light switch is a pressure switch mounted on the brake hose down on the lower triple clamp.

My 650 has it on the brake lever, not sure how 750's were.

[Toxic]

same pressure activated switch on a 77k

Look on the front of the lower triple tree.

After 40 years  by the time we get our hands on these bikes it's hard to say what parts are now on them

[robe0531]

my 78 has the the brake stuff built into the master

[jordanp]

It is all making sense now... The original brake lever/master had the switch... but all my new brake parts are from a 77... I dont have a mounting place for the 77 pressure switch, and my 78 switch was destroyed! so, maybe I need to get a new 78 switch and just use the piston and other mc parts out of the 77. or just run a tail light with no brake light( scary here in CA)

[ekpent]

There are two wires that run off the pressure switch on that brake hose junction on the triple clamp. Make sure you have a good connection on those and they are hooked up farther up in the harness.

[MJL]

A lot of times the tail lights will go out when the brake light is activated, I guess it keeps the bulb from getting too hot and shortening the life of the bulb.  Try a new bulb.