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Discussion Starter #1
Does anyone know what the wiring size is for the handlebar switches etc.? I have to admit I am horrible at determining AWG but am thinking of going with some custom switches and think it would be easier to just run new wire from the junction to wherever I need it instead of Frankensteining the existing forward harness.I know you can always go bigger, but not smaller - so is there an absolute minimum size I can use for all the wiring? I would make it much easier to just buy a bunch of the same wire gauge but in different colors.
 

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They're either 18g or even 20g but that's the easy part. Solder has a tendency to wick through thin gauge wire like lighting resulting in a longer soldered section stiff and non-flexible. There a reason why the factory uses stranded wire whereas the soldered joint is essentially a stiff solid core wire. You might insulate the joints with two incremental sizes and lengths of shrink tubing overlapping them for stress relief.

"What's the absolute minimum size?" 20g is almost impractical to work with even though it has enough conductivity. The factory uses thin gauge just so groups of wires can fit into a single sleeve.

Also the strands in thin gauge wires are thinner and easy to nick with a wire stripper and there's less total strands. If there's only 5 strands in the gauge, each strand represents 20% of the conductivity of the wire. If you use a wire stripper and nick two strands you reduce the conductivity by 40%. You might use a razor blade etc. to strip them so on.

Btw, the stranded wires at Home Depot aren't motorbike wires. If you dissect the factory wires the strand count is higher per gauge. Same gauge, but higher grade Something about electricity flows on the surface of the wire and more strands increase the total surface area.
 

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Good points @RONW, more strands also make the wire more flexible.
A good wire stripper is another one of the tools that is hard to do without, far better than using your teeth or wondering if the cutters are not going to bite right through everything again this time.
I like to use rosin flux and thin solid core solder intended for electronic work, rather than flux core, I find it easier to control how far the solder flows.
 

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Discussion Starter #5
Yikes I didn't even think about that - thanks for pointing out the differences in wires, will go with some wiring designed for bikes/cars when I do it. In regards to soldering etc. I was thinking of running a single wire with no splices between the switch and the weathertite connector under the tank. That way all I have to worry about is the connection at the switch, everything else is crimp. Besides every time I try and solder something it looks like some type of industrial post modern art piece.
 

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As an option to crimping, I've used the Posi-Lock connectors to join wires. They're relatively narrow which makes the joint easy to fit into tight quarters. Also, it's easy to join some of those skinny oem gauge wires. Posi-Lock does offer a water proof connector too (second pic). If you're super bad at soldering, there's self-soldering connectors out there, bottom pic.

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Wire charts to figure required wire diameter based on load and length, scroll down



 

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bear in mind, the shorter distances on a motorcycle would probably be ok with 18 gauge for lower power circuits. also adding relays so just the control circuit goes to the handlebars would let you use smaller gauge wire. for the handlebar switches.

bare a bit more of the copper and use a couple clips, like maybe hemostats on the wire as heat sinks so the solder cools faster at that point and doesn't flow past the hemostats, just dont solder them to the wires,,,
 

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Discussion Starter #9
That solder-splice thing is really cool! I had no idea something like that existed. I used the twist type ones on my old Jeep for the CB and lights so they could be taken off relatively easily and they worked great, but were pretty bulky.

So I guess what I can take away from this is I'm probably good at running 18ga for all handlebar wiring with high strand count - I don't mind if they're a little bigger than they need to be. I guess there isn't a reliable way to determine gauge just by measurements on the existing wire diameter is there?
 

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That solder-splice thing is really cool! I had no idea something like that existed.

Some forum member introduces it to us a few years ago. They're used for avionics and high end thingies, but now they're inexpensive. Perhaps, they're knockoffs. But for our bikes' purposes, they're relatively safe.



  • So I guess what I can take away from this is I'm probably good at running 18ga
  • I guess there isn't a reliable way to determine gauge just by measurements on the existing wire diameter is there?

Go buy some 16g wire and use the sample wire as a reference. Size is a moot issue though since as I understand things, your plan is to splice the aftermarket device's wires to the oem wires. That is, you're joining two existing wires which already have their own gauge. I use 16g and 14g wires but I'll avoid debating the merits thereof. "The factory uses 18g, so if that's good enough for their electrical engineers, why not then use 18g wires?" We'd end up debating whether pluto is planet.
 
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