installing CB550 left side switch onto CL450


New Member
Somewhat experienced wrencher, novice wirer, occasional browser but first time poster of this forum so please forgive me if I'm not approaching this with proper protocol. I tried searching for my issue and didn't have any luck. I bought '72 CL450 off a guy and its a bit of a Frankenstein bike. He bought it without handlebars, tank, seat and headlight. He threw on a CB450 tank, seat and headlight and some handlebars and switches from a CB550 (so he says). It looks pretty cool and the exhaust is in great shape.

I'm cleaning and tuning it up and I want to get it registered as a fun secondary bike so I want the turn signals to work. The right side switch seems to match right up so the headlight switch works and so does the starter button and kill switch. The left side switch has more wires than are what are shown as needed on a 450 diagram including another headlight switch. I've messed with wiring a bit in the past on other bikes but was pretty lucky in that everything matched up and I was just reading diagrams and matching wire colors up. From the diagrams I'm seeing, a CL/CB450 left switch just has 1 orange wire for left side signals, 1 blue for right side signals, 1 light green for the horn and 1 grey for the turn signal blinker for 4 wires total.

With this CB550 switch, there is a light blue and light blue/white wire that should control the right turn signals, and orange and orange/white that control the left turn signals. There is the light green wire that runs to the horn, grey that runs to the turn signal relay. Then there is a black/yellow wire, white wire and a blue wire (these theoretically power the headlight on a 550), so there are 5 extra wires with the additional blue and orange turn signals wires (9 wires total). So the horn, blinkers and blue/white and orange/white are hooked to their corresponding connections in the harness (nothing happens when I plug in the blue and orange wires in lieu of the blue/white and orange/white and there are not enough female ends in the orange and blue sections in the harness to plug both in). I figured since the headlight is working via the connections in the right side switch, I'm not going to connect via this left side switch. The horn does work completely on its own with no other wires plugged in except the light green.

So now here's my problem and where I'm lacking in knowledge (and hopefully one of you reading this is much smarter than me and I'm missing something super obvious). Nothing is powering the signals if I don't connect one of the headlight wires on this left side (either the black/yellow or white wire plugged into one of the spare black connections in the harness). The weird thing is, when either is plugged in, ALL THE TURN SIGNALS ARE ON while the turn signal is in the OFF position. Then, when you put the turn signal into the left position, the left ones turn off and the right side stays on, and vice versa when you put it into the right position. The blinker isn't working in any scenario. So this makes me think there has to be something that is either not plugged in correctly to essentially make everything function the opposite of how it is now (the 12v blinker may be its own issue) or its set up in the switch at the handlebar in a way that is not compatible? I can just buy a 4 wire CB 350/450 switch on ebay for $30, but I feel like I may be one or two steps off of just using this one so why not try to make it work? Anyone have any suggestions on this or missing something I am that may be very obvious? Again, the wiring is definitely my weak spot as I've been able to scoot by on just matching up wire colors in the past, hahaha.


  • IMG_3782.jpg
    2.6 MB · Views: 119
  • IMG_3879.jpg
    931.7 KB · Views: 117
The 550 has double filament bulbs, so your orange/white blue/white are running lights. The solid orange and blue are your turn signal wires. Is that how you have those wired?
Last edited:
The 550 has double filament bulbs, so your orange/white blue/white are running lights. The solid orange and blue are your turn signal wires. Is that how you have those wired?
That is correct. This 450 has single filaments so the /whites aren't being used. After watching the video above I pretty much started from scratch and got it hooked up properly. Everything is working as it should, very happy! I wasn't running power over to the left side switch correctly (it should have been the black/yellow wire from the left side into the brown/white from the right side), and it was all a domino effect from there. Also the flasher relay was dead and wired wrong. I picked up a new one down the street at Autozone for $7 and its all set.
Top Bottom