Topic: 1975 CB750K4, electrical nightmare.

[WhyNot2]

I bought this bike a few weeks ago. I finally got the bike to turn over with the starter button. This thing is swiss cheese as far as wiring goes. I have new coils but no fire to the plugs and the points.

You just don't know how much help i need. *****This is my first*****

No other electrics are connected. Has a new harness and new coils. All other wires are just hanging. I'm interested only in getting this thing to fire. Will be doing a tear down and rebuild in the near future. $$$$$ providing and wife's hunny dew list.

I've ran all the wires to the coils and ignition I think. Are there other wires that I may need to hook up just to get spark to the plugs.
I'll provide some updated pics soon.

[1stgenxxx]

Mine was the same way......I cut all of it out and I'm building a new harness

[Silverback]

The coils are powered through the switch set on the right handlebar. You must either connect that or power the coils directly from a 12V source. Connect 12v to the black/white wires. Of course you'll need to have everything grounded. This can all be done with a few jumper wires, but not so straight forward while trying to use the harness.
This diagram from hondachopper.com simplifies thing a bit:

[WhyNot2]

Thanks Silver, I'll check into that after work tonite.

One thing is that when trying to start it, when I release the starter button, I notice a spark at the spark plug wire.

It only happens occasionally.

[the architect]

Thanks Silver, I'll check into that after work tonite.

One thing is that when trying to start it, when I release the starter button, I notice a spark at the spark plug wire.

It only happens occasionally.

Those handlebar switches get funny with age.  Mine had plenty of bad connections inside it.  I ended up dismantling it, cleaning and resoldering the connections I was going to use, like the starter button.  After my accident, I had to replace the left-hand controls.  The replacement I bought had spiders living in it    Needless to say, after evicting those guys, it needed a thorough going through.

To power the coils just for trying to spark the bike over, you can jump them straight to a 12v source - even the battery, if you like (you might condider running a fuse there, just in case).  Then you'll just disconnect that 12v source to kill the engine.  I have a friend whose chopper runs this way all the time - no key or switch, just connect the coils to the battery with the quick connector and start the bike.  He unplugs it when he get to his destination.  No one would get very far trying to steal his bike, though - the clutch and brake are switched, and it's jockey-shifted behind the rider's leg (no clutching up-shifts).  In other words, it's takes a lot of practice to get the hang of riding.

[WhyNot2]

Well, not much happening, still no spark.

Did, however, get some 11 inch rear shocks and slid the fork tubes up into the trip's to lower the stance alittle.

Not sure if I mentioned it, but this is going to have to be a very, very low budget rat/bobber bike. Being done with simple garage hand tools.

Hell, its so low that I'm doing it in my storage shed in the back yard with no electricity.

So will probably be slow going, due to getting laid off a week here and a week there.

Help is surely needed and very much appreciated.

Soon as I get pics, I'll post.

Jack