Topic: TSUNAMI-1978 CB750 K8 DONOR TO CAFE'

[SOHC4 Cafe Racer Fan]

You are a brave, patient man, Greg.  I probably should love wiring.  It has a logical, flowchart order to it.  I just lose my mind with the rats nest and tracking down shorts (a problem I've had on two bikes).  I contracted out the wiring to some wiring wunderkind kid who re-did both harnesses from scratch -- and no more wiring issues.  I bit the bullet on my next build and bought a Motogadget M-Unit and M-button. 

[calj737]

Just so you know, Don, gotta run resistor wires with the M-button. Too much interference from the ignition or something that causes a few glitches with it functioning properly.

I'd sure use one on Tsunami's build though (M-Unit). Simplifies everything'!

[Tsunami]

I really wanted the M-unit but a little too rich for my pocket these days so I went with the PDM60, still trying to figure out the negative trigger on that one.  I will though. No takers on the Relay question, huh?  I did find a place on the board that appeared to be the place to ask but no results yet.  Been getting some work so not  much time for the bike at the moment, its good to step away and go at it fresh another day.  As long as I remember what the heck I was doing.

[brandEn]

I can attempt to answer your question as I understand it....

The engine "kill" switch is a normally closed switch that basically is just an on/off for power to the coils. I don't believe there is any ground to the switch itself. The black power wire goes in one side of the switch and the black/white wire comes out the other side and powers the ignition coils. Lots of us on the forum including myself have used an automotive relay to power the coils. You use the kill switch to power the relay and run a hot power wire directly from your battery through the relay to power the coil. You use a good ground on the grounding terminal on the relay. Make sense?

[Tsunami]

I think I have it! So the black/white wire is the power to the coils, it is fed by the black common wire through the stock switch which I no longer have and will use the relay as that switch. What I need to do is interrupt this black to black/white wire until the engine stops. I use the relay to do this by energizing  the coil with the small switch which is grounded on one wire and the other to 86 pin and 12v on the 85pin.  Push the switch to close the circuit, that energizes opening the normally closed relay with the common black wire on pin 30 running through it to the 87a wire that is the ignition feed wire (black/white) opening that circuit which interrupts the power killing the engine. Once the engine is dead I release the small switch which close's the relay (resets) I always get confused about the black wire as it was always the ground back in the day now its green, so is that my power wire or like you say run a dedicated hot wire from the battery?  Wouldn't you want the 12v switched through the ignition as your power lead?  I think were close and thanks for your help brandEn.

[calj737]

Wouldn't you want the 12v switched through the ignition as your power lead?

Yes, BLACK from ignition switch is the better 12v source. It is the same wire running to the KILL switch in the stock config.

[brandEn]

So the kill switch you want to use is a spring loaded deal that you have to hold? If your not pressing it the contacts are open but when you press it the contacts close? Originally the kill switch is always closed and when you flip the switch it opens breaking power to the coils. I guess the way you want to do it would work you just need to make sure the you connect the power the coils from the battery through pins 87a and 30. When you energize the relay coil through pins 85 86 it would interrupt power through 87a and 30.

Actually now that I think about it if you do it this way your coils will always have power. Even if your bike is turned off. Not sure thats an ideal or safe way to do this. But like I said Im no expert! Hopefully someone else will chime in. Two Tired would be perfect. He is real good at this stuff.

[brandEn]

as an FYI I love these little micro relays. Much smaller and easier to stash on your bike
http://www.easternbeaver.com/Main/Elec__Products/Relays/relays.html

[Tsunami]

Should make no difference as the stock switch is always closed as well.  Yes he has good stuff, if that is the four pin that is always closed, most are always open. He didn't have it in stock when I needed it but as it turns out I have the five pin that works as well and its more than small enough.  Thanks everyone, I feel more confident that this should work.

 Now for something completely different, do I still need the diode for the starter if I don't have the clutch switch? Seems as it is only there to prevent the starter from energizing when the clutch switch is close.  So no switch, nothing for the diode to do??

[BPellerine]

Greg I downloaded the wiring diag that branden posted and then had a guy with a BIG printer make it about 2 ft  by 3ft so I could hang it on the wall ,easy to work from.bill

[brandEn]

Nope don't need the diode. I just removed mine and the wires.

[Tsunami]

I hear ya Bill, been there done that, thanks for the incase though

[Tsunami]

Great two less to worry about, thanks brandEn

[BPellerine]

way ahead of me greg!your bike is looking great!bill

[Tsunami]

For those of us who are confused or have aged and forgotten I will provide this from the FAQ section special thanks out to Jonesy-- THIS IS THE BIBLE!!! ALL IS REVIELD! THANK YOU, THANK YOU!

Found it in FAQ under electrical

More from Jonesy:

(I put this together after a few questions about the wiring in these bikes. Some suggested this be put in the FAQ. Hope this is helpful.)

Here’s a general wire guide for the 70’s Honda SOHC/4’s. Some of this may be different for the 650 (I’m mostly familiar with the 350, 400, 500/550 and 750) or bikes factory-equipped with electronic ignition. Consult your manual for specifics.

Main Color/Tracer Stripe Color- Description (Approximate Path, if Applicable)

All Circuits
Red- Constant Hot From Battery (Battery Terminal-Main Fuse-Key Switch)
Black- Switched Power Supply Buss (Throughout motorcycle)
Green- Ground (Throughout motorcycle)

Lighting
Brown- Tail Light Power (Main Switch-Tail Light)
Brown/White- Instrumentation Backlighting (Lighting Switch-Instruments)
Orange- Left Turn Signals (Turn Signal Switch-Front/Rear Signals)
Orange/White- Left Front Marker (Light Switch-Marker Lamp)
Light Blue- Right Turn Signals (Turn Signal Switch-Front/Rear Signals)
Light Blue/White- Right Front Marker (Light Switch-Marker Lamp)
Gray- Pulsing Power for Signals (Flasher Relay-Turn Signal Switch)
Blue- High Beam Power (Hi/Lo Switch-Headlamp/Indicator Lamp)
White- Low Beam Power (Hi/Lo Switch-Headlamp)
Brown/Red- Fused Headlamp Power (Fuse Box-Hi/Lo Switch)

Ignition
Black/White- Coil Power Supply (Cutoff Switch-Coils)
Yellow- Breaker Signal, Cylinders 2&3 (Right Points-2&3 Coil)
Blue- Breaker Signal, Cylinders 1&4 (Left Points-1&4 Coil)

Starting/Safety/Monitoring
Blue/Red- Oil Pressure Signal (Oil Pressure Switch-Indicator Lamp)
Red/Green- Neutral Switch Signal (Neutral Switch-Indicator Lamp-Safety Unit)
Green/Red- Clutch Switch (Safety Unit-Clutch Switch-Starter Button)
Green/White- Horn (Horn Button-Horn)
Yellow/Red- Solenoid Signal (Starter Button-Solenoid/Safety Unit)
Green/Yellow- Brake Light Power (Front Brake Switch/Rear Brake Switch-Brake Light)
Brown/Blue- Turn Signal Pickup (Turn Signal Beeper-Turn Signal Switch)

Charging (3-Phase External Excitation Systems)
Yellow- Stator Coil Output (Stator-Rectifier)
White- Field Coil Supply (Field Coil-Voltage Regulator)
Red/White- Positive Rectifier Output (Rectifier-Battery)

[Tsunami]

 
Made myself a nifty starter solenoid bracket out of a piece of extra aluminum bar stock.  Not real Purdy but will clean it up later.  Still need to bring the tangs in a little more.  When I'm ready to mount it I'll pull the unit and bend in the top of the tangs to hold it from dropping out as it will likely be mounted upside down.

[Tsunami]

Worked on the Battery cables and my dads plaque from WWII, He was a tail gunner in a B-24 and they were hit by flak.  Luckily he was not wounded but one of his 2 .50 was jammed by shrapnel that hit is ammo.  Many years ago he mounted it on a plaque along with some other stuff.  Over the years it tarnished and got beat up a little. So I took it apart buffed the brass repaired the mount for the bullet etc.  Some parts a drying when I get it finished I will post a photo.

[Tsunami]

Mo

[BPellerine]

jeez greg do you have a weapons stash!!!?haha bill

[Tsunami]

1-Picture of my next build, yes bill I'm locked and loaded, can't be too safe these days!
2-Picture of my Dad next to his turret on his B-24 Liberator "PADDLEFOOT"
3-Picture of me next to my turret B-52 Stratofortress D model
4-6-Pictures of my dads Plaque after I fixed something's and cleaned it up

My dad and I are about the same age, 20.  I took a flight in a B-24 some years ago, I manage to get one leg in the tail turret, wasn't going to happen but it sure was a gas to fly in.  Had to imagine climbing into one of those tin cans, flying for hours at 20-30k with temps -25 to -70 degrees.  Wearing an electric suit under heavy shearling outer gear, gloves, goggles and boots made for the Klondike. (sort of like riding bike in bills winters) All the while shooting at a moving target flying in excess of 200mph while it was shooting back.  Back then it must have been like being Flash Gordon on a mission to rid the world of evil!  They were Air Men going to battle with what was at the time the leading edge of Technology of aviation. WoW what a rush.

[Tsunami]

Now for something completely different, motorcycles.  I'm still messing with the wiring, tried to do Hondamans rebuild of a starter solenoid.  Did great, wasn't too bad, had it all done then while putting the cap back on one of the two screws got misaligned and pulled the yellow/red wire out from the electro magnet.  Now its junk.  So waiting delivery of a new repop. This thing is still bleeding money.  I'm trying to work out some new weather proof connectors especially the one from the motor stator.  I'm going to lengthen it a bit so the connector will be under the seat.  I'd say I have about 75% of it figured out but I cant start putting it together until everything is worked out.  Then I can   do all the wire cutting to size, then take it all out for wrapping, I'm going with a lot of silver sleeve's, also will have some silver tape for what I cant sleeve.  Once that is done I can install all the appropriate connectors. Things are falling into place but its as bad as buffing all the aluminum, not quite as dirty though.

I have also decided no more polished look to the tanks and seat.  I thing I have found a silver I can live with.  Will redo the seat first as it is the smallest to test the paint on.

One last look at what I'm giving up on.  The Manx tank that looks dull is sanded for its last coat of clear but I was not happy with the outcome so going to white primer over it and repaint.

The seat is just sitting there the snaps have been removed to facilitate painting.

[SOHC4 Cafe Racer Fan]

Sorry to hear that tank/paint is putting up such a fight. I like the inspiration - great pics, Greg!

[BPellerine]

what kind of bike is your dad? riding in the pic looks familiar but cant id it .bill

[Tsunami]

Bill, that's not my dad its just a crazy war picture I thought would make a funny opener to the update.  Best guess he's French.

[BPellerine]

ok back to bikes now.haha bill