Topic: CB750K Starter Button Fix? (right hand switch)

[saw750]

I was replacing the cable on the old 1976 CB750K and I noticed that the starter button stuck. After further investigation, I discovered that the internal housing surrounding the button itself was brittle and cracked in several places.

The wires are intact and in good shape its the lil rectangle plastic surround that is junked and shattered

Is there a replacement available??? (off other models?) or do i have to replace the entire right handle bar switch? (I see OEM on ebay for $100 +/- ugh!)

I know its not the end of the world there is always kicken but still i would like to have this functional.

Is there a hack available? I dont care whats going on inside the switch as long as it works

thanks in advance - saw

[blaster802]

If's its just the button itself I was able to get one about a year ago. I think it was from bike bandit.

[xenoscr]

Partsnmore.com sells a replacement. They have $35 minimum order though.

https://www.partsnmore.com/cat_index.php?model=cb750_sohc&category=electrical

XeNoSCR

[saw750]

i am not sure what i need. basically, when i opened up the right control the "plastic box" that the wires feed and contains the button mechanism "disintegrated"

[Duke McDukiedook]

Partsnmore.com sells a replacement. They have $35 minimum order though.

https://www.partsnmore.com/cat_index.php?model=cb750_sohc&category=electrical

XeNoSCR

Odds are you'll have to file or sand off a good portion of that brass plunger in that kit.
I did.

[Deceptibong]

Partsnmore.com sells a replacement. They have $35 minimum order though.

https://www.partsnmore.com/cat_index.php?model=cb750_sohc&category=electrical

XeNoSCR

Odds are you'll have to file or sand off a good portion of that brass plunger in that kit.
I did.

same for me too...

[xenoscr]

Partsnmore.com sells a replacement. They have $35 minimum order though.

https://www.partsnmore.com/cat_index.php?model=cb750_sohc&category=electrical

XeNoSCR

Odds are you'll have to file or sand off a good portion of that brass plunger in that kit.
I did.

same for me too...

Good to know. I'm on my 3rd starter button. The first two disintegrated beneath my thumb. I was thinking about trying this kit next since it's new parts opposed to the old I've been lucky enough to salvage so far. Still if I just have to sand or grind some off this kit to make it work, that's not too hard.

XeNoSCR

[rhos1355]

Mate of mine refashioned a right hand switch assy from 3-4 odds and ends ones I got from bike sales etc. He did an excellent job and everything works albeit the wires are now the "wrong" colour. But............they are a bugger to feed through the handlebars.
He said that anybody with an electrical diagram and a bit of electrical "nouse" could do the same.

[Alan F.]

You can get a momentary push button switch from radio shack that will work just fine since this isn't a very high current application. Their tiniest switch fits in place of the stocker too.

http://forums.sohc4.net/index.php?topic=29968.0

http://forums.sohc4.net/index.php?topic=12586.msg120462#msg120462

And it turns out that the horn button is the same part and will work as a starter button if you can find one.

-Alan

[xenoscr]

And it turns out that the horn button is the same part and will work as a starter button if you can find one.

This was not true on my bike. The internals of the button are different.

XeNoSCR

[saw750]

just so we are all on the same page

see the the item labeled switch housing? that is what i am missing (yes, that is from a different model but it is of similar design)

[westondc]

And it turns out that the horn button is the same part and will work as a starter button if you can find one.

This was not true on my bike. The internals of the button are different.

XeNoSCR

yep, you have three wires to the starter button. mines the same, its a 76' 750. one of those three wires goes to your headlight circut. correct me if i'm wrong but i think the original switch was meant to kill the headlight when you cranked the starter. i installed a radio shack (two post) push button and it works just fine. you have to solder two wires to one post and the other wire to the opposite post. download a wiring diagram and you can figure out which wire gets soldered to which post.

[westondc]

if you need some help figuring out the wiring just let me know i can look it up again. also... the radio shack hack will save you some $ over the OEM alternative. cost about $4 @ the shack

[saw750]

The radio shack momentary switch sounds like the way to go! especially if it fits in place of the original. now i just have to find that switch. lol. (radio shack isnt what it used to be lol - typically, whenever i go in there and ask for something specific the kid behind the counter gets a puzzled look on his face and says "wha?" lol)

[westondc]

The radio shack momentary switch sounds like the way to go! especially if it fits in place of the original. now i just have to find that switch. lol. (radio shack isnt what it used to be lol - typically, whenever i go in there and ask for something specific the kid behind the counter gets a puzzled look on his face and says "wha?" lol)

here's the one i installed Mini SPST 0.5-Amp Momentary Switch http://www.radioshack.com/product/index.jsp?productId=2062539
it will fit perfectly just be carefull when threading the nut on the switch, it's poor quality and the threads may strip.

looking at the wiring diagram (combination switch, bottom center of diagram) i'm not exactly sure how i wired it up. i used a volt meter and some trial and error. Maybe it was BAT, IG wires to one post of the button and TL1, TL2 to the opposite post

[lucky]

The radio shack momentary switch sounds like the way to go! especially if it fits in place of the original. now i just have to find that switch. lol. (radio shack isnt what it used to be lol - typically, whenever i go in there and ask for something specific the kid behind the counter gets a puzzled look on his face and says "wha?" lol)

Many stores are that way now.
At Sears the sales people in the tool dept. do not even know the names of the tools.

The 1976 Honda CB750 switch is not as good as the 1975 switch.
The 1975 switch keeps the headlight circuit separate from the start circuit.
You start the bike THEN turn on the lights.
The later models did not trust you that you would turn on your headlights.
They made the later switch cut out the headlight while the start button was depressed and then when you let off the start button then the headlight circuit was activated.
The only problem is that with all that current going through that switch it gets very hot and melts.

Ask any VFR honda owner about start switches.
Also all of those bikes had problems with rectifier plug- ins getting overheated.

[Spanner 1]

Yep, Lucky is right........... Riders can't be trusted to remember to turn-on their headlight so the original r/h switch that had a separate h/l off- on-low-high switch had to be changed to the start/headlight combination push button, which at best is too physically small for it's contacts to survive the current demands on it over time and the thin housing goes brittle and breaks-up too..... very common.
Old farts like me have a routine before moving off that includes sitting on the bike and testing the brakelight, placing a hand over the tailight to check if it's on and also over the headlight to check for illumination every time.... purdy good habit IMO. 

[BeSeeingYou]

If you are going to run the headlight through that radio shack switch like the stock set up you had better get one rated for more than .5 amps.  The headlight circuit has a 7 amp fuse so unless you want the switch to become the fuse get something rated in that range.

[HondaMan]

You can use a simple grounding switch for a start button IF you also do the following on that bike:
1. Bypass the Safety Module, tie the Green/Red start solenoid wire to an available Black wire instead.
2. Install a relay (like my Start Button Saver kit) that uses the NC contacts to power the headlight circuit from the same Black wire (to relay COMMON contact) in the headlight that used to power the old Start button, with the Bk/Rd wire (some are Bk/Yl) to the middle fuse coming from the NC contact. Connect this relay's coil to the Black wire circuit in the headlight, and the other side to the Start button (Yellow wire circuit).
3. Connect the Yellow-Red starter solenoid wire to the new Start button so it grounds when pressed. This turns on the relay, which turns off the headlight, while the Start solenoid turns on.

I off these Start Button Saver kits to, well...save these expensive Starter buttons from an early death caused by halogen headlights.