Topic: A couple wire harness questions

[thomellis]

Hey Guys,

So my bike (72 cb750) for all intensive purposes is a K2 (at least from what I know, engine, frame tag), but there are a few mis-match parts that clearly came off of some other bikes that the previous owner put on.  The wiring harness in particular I'm pretty sure is from a later model bike, k3-k6?  At any rate, it has a few extra wires that my bike doesn't need, and some other area's were falling apart, so I've unwrapped the whole thing, made some repairs here and there, and come across a few questions I'm hoping someone can confirm for me.  I searched around, but I couldn't seem to find the answers, so I apologize if I've missed a post elsewhere.

This harness has a connector for a "starter motor safety unit", which as far as I can tell was only on later bikes, and I'm pretty sure I can just remove this.

I think all bikes had what is listed as a "combination switch" in the K2 manual, but later schematics call it out as an ignition unit.  Either way, there is nothing on my bike which can connect here.  Do I need branch off the harness at all?  Any reason not to take it off?  It was never connected before, but is there any reason I'd want it there in the future?

Lastly, since this is an older harness, it has the 3 fuse setup, instead of just the 1 fuse typical on a K2.  It obviously worked before, and as far as I can tell, it makes the electrical system more protected by not relying on one fuse, but I just wanted to check if there was any downside to leaving this in?  (fwiw, I'm going to switch to blade fuses as well)

Thanks!

[bjbuchanan]

If it is already switched over to the three fuse style, leave it. If it has a k6 harness on it it will have power running to the starter button and a yellow/red as well as black/red off of it. New mandates meant headlight on all the time The earlier is a grounding style button and you have a separate off/low/high switch

I'm not sure what is running to the starter unit, if its just 'there' delete it. K6 uses a clutch safety switch and a neutral switch with a diode inline. Either of the combos are just a redundancy thing that is used because Honda wanted the masses on their bikes, even clowns who don't look for neutral when the are starting, or atleast know to pull in the clutch. In a later harness you can ground the green/red, take the wires out of the clutch perch and delete the diode from the system and straight wire the neutral wire from switch to light.

The ignition switch is a combination switch. How do you turn on/off the bike? A key, switch, some other james bond contraption maybe?

[thomellis]

Thanks bj.  From what I can tell, it's just "there" so I'm going to take it out and slim things down a bit.

As far as the ignition switch, i wish it was some exciting james bond contraption, but it's just a simple key switch, however it only has 2 wires with bullet style connectors that look like they just attach to the harness. See below:



There isn't anything on the bike that I can find which attaches to this connector (which is called the combination switch), at least that I can tell.




Thanks again for the help.

[bjbuchanan]

Your empty plug is where the keyswitch plugs into. He essentially jumpered it with his own. If it all works then trace your wires and compare. He must have needed a keyswitch and just made due with what he had. You can undo and reuse stock keyswitch or get all fancy like with your own setup

Go to oldmanhonda.com and stare at the interactive stuff

[thomellis]

Thanks again BJ.  After some studying of the diagrams, I actually put it back on the bike just to make sure I understood everything as well as I thought I did   I ended up taking off the connection, connecting the lights, so I'll lose the parking light only option, and I'm just going wire the 2 wire switch inline to control power through the harness.  Cuts down on the extra wires a bit, and I'm not to concerned about the parking lights anyways.

Soldered everything up, and fixed up a few bad connectors.  Now, I just need to wire up the new fuse block, and re-wrap everything and I should be good to go.  Fingers crossed.

[bjbuchanan]

Clean up the connectors while you are there. Use a wire wheel in a dremel or something similar. You don't want to take material off of the bullet, then its a sloppy fit so avoid sandpaper

Depin the blocks and wheel them because they are probably as rough as everybody elses when they start out. (.17) inch rifle brush cleans the female part. You can improvise but the brush is real easy

The parking light is pointless anyway, no one uses those things. The way I look at it, any other vehicle when you get out or get off you turn the lights off so you don't drain the battery right?

I am finishing up building a harness with relays for hi, low beam and coils along with a hondaman ignition so fire away with questions before I forget

[74750k4]

What do you plan to re-wrap the harness with???

Not electrical Tape!!!???

Use plumbers emergency tape. Available at ACE Hardware, etc. Perfect for wire harnesses. Leaves no gooey tape residue on your nice clean wires, because it doesn't use that. It sticks to itself when stretched.

[bollingball]

What do you plan to re-wrap the harness with???

Not electrical Tape!!!???

Use plumbers emergency tape. Available at ACE Hardware, etc. Perfect for wire harnesses. Leaves no gooey tape residue on your nice clean wires, because it doesn't use that. It sticks to itself when stretched.

http://stores.ebay.com/Atop-Authentic-Auction/PET-Expandable-Sleeving-/_i.html?_fsub=2578659015&_sid=879188535&_trksid=p4634.c0.m322

http://www.techflex.com/howtos/workingwithtape.pdf

http://www.cableorganizer.com/techflex.htm

[thomellis]

thanks for all the tips.  definitely want to go through and clean things up. 

I already picked up some plumbers wrap, read lots of good things about it.  I bought 2 rolls right now (20 ft.), any idea how much you need roughly?  Obviously it will vary based on who's wrapping, but ball park.

If I come across any other questions, I'll definitely ask bj, thanks. 

supid moment:  In case anyones curious, "Depin" is also some medical product, A potent vasodilator agent with calcium antagonistic action.  I read that quick and thought it was just some cleaning solution or something at first haha  I'm straight now though :p

[TwoTired]

So my bike (72 cb750) for all intensive purposes is a K2 (at least from what I know, engine, frame tag),

To keep those knowledgeable of English phraseology from snickering at you, be aware that the phrase is "intents and purposes" rather than "intensive purposes".

You can usually get away with the error in the flow of speech.  But, when printed out, its rather funny.

FYI

Cheers,

[bjbuchanan]

Lolol^^^