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Discussion Starter · #1 ·
I purchased my 1973 CB350 Twin with a ginormous mess of a wiring system. I replaced the battery, stator (Rick's), and rectifier/regulator (Rick's), but the rest is a mess:

-horn switch triggers electric start
-electric start switch does nothing
-high beams switch in the low beams position is the kill switch
-can’t figure out how to wire the horn I bought because there’s no previous horn
-brakes don’t trigger the brake light (front or rear)
-wires seem stiff and old
-electric starter motor is shot (not a big deal to me - kick start)

Since the previous owner re-routed the wires, what's the best way to solve this? Would a new harness be the best option so I can start fresh with good wires and a diagram that makes sense? New switches, too?
If so, what's the best harness for your dollar? A local shop recommended Sparck Moto, but that's way more expensive than the Dime City one.
Thanks!
 

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First you need an accurate wiring diagram for your bike in order to identify why you are having issues. Do not attempt to troubleshoot without a diagram unless you are familiar with the wiring already.

If I were in your position I would make a list of the things I want/need, for example: don't want E start, don't need E switch etc...

Then Identify where the wires are for the things you DO want and how they compare to your wiring diagram.

Check the overall condition of your connections and wires. I have never bought a new harness for any of my Hondas. Your bike may be different.

Unless the PO really ****ed up the wiring there is no reason you shouldn't be able to fix this yourself. Get some zip ties, appropriate gauge wire, bullet connectors, heat shrink, vinyl tape and a bullet crimper and you can do all of this work yourself.

Take your time and study your schematic.
 

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I had the same issue and went for a new harness from alans-electrics on ebay (UK). Very good harness. It feels good to get rid of the ratty, old one and start wiring from a nice new loom. It also helps to weed out faulty components. I used the manual wiring diagram to wire everything, it takes time.. Word of advice: don't throw the old harness out until everything on the bike works with the new one. Sometimes its helpful to reference the old loom and sometimes snip off bits and use them. Good luck
 

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Send me a picture with your email address. I have a PDF of the service manual with the wiring diagram.

Sent from my Moto G (4) using Tapatalk
 

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If you have time and patience to spend, you can try working with your existing harness. If you're short on both then another may be best
 

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Discussion Starter · #6 ·
Thanks for the info! At this point, I'm thinking it'll be better to start fresh with a new harness. I will just feel better about all the wires on my bike if they are fresh. Are the ones on eBay just as good as Dime City or other harnesses in your experience?
 

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Sound's like the PO monkeyed with the wires un till he got some things to work. I'd reconnect the wiring where it belongs and trouble shoot it from there. I've bought harness's off eBay, but it's a gamble, you don't know what you're getting un till it's in your hands.
 

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I can vouch for the Sparck harness.. same thing happened to me, the PO jerry-rigged all the wiring, things were cut and plugged into the wrong terminals, some of the wiring was visibly fried...

Wiring is my weak point too, I’m always intimidated by wiring, but the Sparck harness made it easy.. gave me piece of mind to know that it’s all new now, if something isn’t working, it’s most likely the component itself and not the wiring..

Like someone mentioned earlier, save your old harness once you pull it off, sometimes it’s good to reference and if you need to clip any fittings or wires off, there’s a lot there. Also take photos of clusters as you are disconnecting the old harness, good to reference the photos as you are putting the new one on. Just follow the factory manual wiring diagram, break it down into sections.. Get some quality connectors and a good crimper, you’ll need them, makes it a lot easier. Vintageconnections.com (I think it’s the same company as Sparck) has a bundle kit.
 

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Awesome! Very helpful. Shane, how long did that project take you?
Hey Jcoats... I took my time and had it wrapped up in a couple hours. I was really expecting it to take longer, especially after reading a few threads where people discouraged swapping out the harness. I'm still missing a few things such as blinkers and a working left-hand switch, so I haven't got ALL the wiring hooked up at the moment. But it starts, headlight works, neutral light works etc..These 350 twins are really pretty simple compared to many other bikes.
 

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Discussion Starter · #13 ·
That’s great news! Talked to another guy who said it took him a few months worth of weekends to finish... said it will take me much longer than I expect.
 

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The way I see it, Sparck Moto is worth every single penny. You can even opt for labels on the wires.. which makes it that much easier. And customer service is fantastic. If you're going to get a new harness, just get a Sparck Moto otherwise some companies don't use the stock wiring colors. I can't speak highly enough of Sparck Moto.
 

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Discussion Starter · #15 ·
You can even opt for labels on the wires.. which makes it that much easier.
Love the fact that you can order with labels on wires....so awesome. A local shop is going to quote me on them doing the work. If it comes in around $300, as they guessed, would it be worth having them do it? Or should I buy the Sparck harness for $120 and do it myself?
 

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IMO, you should buy the Sparck harness and do it yourself. Obviously I don't know the reputation of the shop in question, but we see so many situations where a local shop that generally does decent work is baffled by a vintage bike, largely because most (if not all) of their people are younger than the bike they're working on. You'll get all the help you need here, particularly from Sonreir from Sparck Moto for their harness. The 350 is not a complicated bike electrically, and half of your issues with handlebar functions are probably mis-wired in the headlight bucket. Get a good harness in place, properly connect the handlebar switches and most of your issues will likely clear up. Check to see that the short ground wire for the handlebars is connected between one of the gauge mounts and one of the nuts on a handlebar mount to be sure the bars are properly grounded for the horn and starter button circuits to work correctly. the brake light switches are just as simple, power to one side of them (black wire) and the other side (green/yellow) goes into the brake light circuit in the harness. That, and a good ground on the taillight assembly, should give you a brake light from both switches
 

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It shouldn't take you more than an afternoon to fit the harness. Buy the sparck one and some zip ties and Velcro. It's really pretty easy.
 

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I vote with the do it yourself crew. I dont know where you live but its January you should have plenty of time before riding time and the learning is worth the effort.

Bill
 

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The wiring really is daunting when you haven't done it before. BUT I would say do it yourself, then from now on when you need to diagnose and fix something you know what to look for and where to find it. Again, if someone is doing it other than you and they change the wire colors it makes it more difficult to rely on the factory wiring diagram. You can do it dude, we believe in you
 

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It's really the old saying of fearing the unknown... with the Sparck harness using factory colors, it will plug into all the functions on the bike as designed so there will be little confusion. Routing it will create as many decisions as the connections, which won't be many... cb360j is right - you CAN do it, dude, and we're all here to help along the way
 
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