Basic Motorcycle Electrical Theory - Revival Cycles' Tech Talk 

Great explanation

I was very intimidated to start a rebuild on my Suzuki 1973 TC125, but watching Stefan and these Revival Cycle videos have given me such confidence as well. I bought the M unit Blue and wiring kit, I’ll let you know how it goes 👍🏽

Glad to help!

Thanks for the clarification on that.

Glad it was helpful. This video is for an outdated m.Unit and left here for a general reference. There are updated guides and diagrams for the m.Unit Blue on our knowledge base. technicalarticles.revivalcycles.com/hc/en-us

Thanks William, Be sure to check out our Tech Articles page on our site. We go into more depth there and you'll find diagrams for Reg/Rec integration that may help you sort out your issue. technicalarticles.revivalcycles.com/hc/en-us

What situation do you need a lock to hold your seat on? I imagine it might happen in LA or NYC but I've never heard of someone rummaging under a bike seat. If someones serious about stealing your bike there's no seat lock that's going to stop that.

Many thanks!

On most bikes the entire metal part of the frame/engine/handlebars/etc is "ground". Basically anything metal that touches the frame. This is why there is a large battery cable that goes from the battery negative terminal to the frame or the engine. Although you can simply connect each device to the frame/engine/etc to ground it, experience shows that this is not as consistent or reliable as it could be. For this reason, we will actually run a dedicated ground wire to each device so there is no doubt that the connection is secure.

Be sure to check out the tech articles page linked in the description. This is a good overview but also really dated, this m.Unit V.2 is no longer available.

Claire Lensegrav He’s done a good job with the video, however for wiring up an entire motorcycle youll need to research a lot more. This is more of an “ELI5” version of electricity. It’s serious, you could fuck yourself up or the entire electrical system.

That's a great suggestion, and we will add it to our list. I know jetting is much more of an art than a science (really its all science but its an applied art for most home builder) still we can cover some basics, and give a process and platform for learning the art.

Revival Cycles cool!

sweet! can't wait for this one!

excellent suggestion!

what an utter load of shit Bruce you cockwomble

Awesome! Thanks for clearing that up, always love knowing why things are the way they are.

You still know more about motorbikes than me :-)

P. S. in case you're curious about the shotgun pellet sizes --> the archaic way this came to be was: take a ball of lead that weighs exactly 1 lbs. Now divide that ball into small, equal size balls. Depending on how many smaller, equal sized balls you divided them into is the "gauge" of those small balls. I. e. if you divided the big ball of lead into two balls, those were "gauge 2". If you divided the big ball of lead into 50 small balls, those would be "gauge 50".

Glad it was helpful!

The rivera primo is the only headlight we've used that has integrated turn signals, we've shot a video for it, but its still being edited. In general I'm not a fan of turn signals in the headlight because they don't really work as turn signals. This is because they are over powered by the headlight and even if you do notice the signal you end up having to look directly at the 1000 lumen headlight. BUT if you are just trying to meet an inspection requirement they might do the trick. While the integrated headlight turn signals may not be effective turn signals, they could be effective for passing inspections. Either way, this is a matter of preferences, and if you like em, the rivera primo headlights are reasonably well build, and have models to fit a standard 7" or 5-3/4" shell.

...I agree....some cars even have the turn signals right in the headlights.....this seems pretty ....uhm.....stupid by the design engineers....maybe they don't drive at night?

Aviation specs are great, but I wasn't able to find that exact document easily...maybe I need to go practice google some more. But also, on the moto's pretty much all the wire runs are less than 6 feet and that makes the chart less necessary...and that is why I just stick to the rule of thumb. Oh and that is for the over current protection, not what the circuit is actually consuming. 22ga -5 amps 20ga -10 amps 18ga- 15 amps 16ga- 20 amps 14ga- 30 amps 12ga- 40 amps

Revival Cycles fair enough. Looks like I can't spell anyway. Thanks again for taking the time to make these videos! I'm gonna send the link to this the next time a friend calls me and wants me to wire their bike for free.

So does the electrical potential (V) drop at each point that work (A) is done along the circuit? Im referring to the end of the video where you explain that the circuit has equal potential after the battery, and then equal again after work is done powering lights? But its not equal to what it was when it left the battery ie before the work was done? Damn I thought I understood this. If I'm right wouldn't that mean the more times you splice in to run more lights you would end up running out of V to power the last bulb? Or it would be dimmer than the others? I think I know lol that it has something to do with wiring in series and parallel, I can remember doing this experiment in science with the globes in the wooden board but that was so long ago. I think this is what the control m board thing is doing isn't it? Because that all made sense as you drew the wiring diagram for that bike. But the end of this one you said we just have to know where to splice in on the circuit for that component, somewhere that it has equal potential, I think thats what you said lol, I tried to get my head around that and seem to have been going around in circles sincd lol. This whole post probably doesn't even make sense lmao. I dont think I have the potential needed, my bulb is definitely running dim lol

I'm not sure I understand the first question, in that section of the video i'm mostly explaining that the voltage is the same anywhere along the wire between components. So in the example you mentioned above, if you splice into the positive wire near the bulb it is the same as splicing into the wire at the positive source. As far as grounding aluminum is a very good conductor, but many times it will have anodizing as the outer skin and that is a non conductive surface. So if you need to conduct through aluminum make sure you get a connection to bare aluminum. It is not uncommon for us to find issues with ground connections through handlebars because the bars are powder coated or painted or anodized. Also, there can be issues trying to conduct large amounts of current through steering neck bearings, and this is why we recommend running dedicated ground connections and not just relying on the frame. That said, fundamentally there is no issue with different metals, and the majority of metals on a motorcycle conduct very well, and that is why many manufactures will just use the chassis as the ground connection. Lastly when running grounds through the chassis, there is the possibility to increase galvanic corrosion across the interface of dissimilar metals, but this is getting deep into the minutia and is negligible for most applications.

Speaker wire is gernerally not rated for the same harsh conditions of heat, moisture and fuel that automotive wire is rated for. Ideally you want TXL or better wire.

You can wire the m-Blaze Pins into the factory harness, but you will also need to replace the factory turn signal flasher relay with a relay designed for use with LED's. There are many direct fit replacements that you can probably find information about on the triumph forums, but I typically just install an m-Flash because I am more familiar with them and I know they work. I've had problems trying to use some of the direct fit type. The m-Flash is easy enough to install, just crimp some 1/4" spade terminals on the wires and plug it into the socket where the old relay was. The red wire needs to be connected to the positive power source and the black wire feeds the turn signals.

If the regulator is integrated with the CDI then it is a system I am not familiar with. The best recommendation is to get a copy of the factory wire diagram and then isolate the charging system by tracing the wires that are connected to the reg/rec. Then you can also isolate the ignition system, by tracing all the wires that are connected to the CDI.

Yea, that is the part of EFI bikes that makes re-wiring a challenge. Make sure you have a good wire diagram and make sure you have a clear understanding about how it all works before starting. The ECU's are sensitive and if you put +12V or ground to the wrong pin it can brick the whole ECU. In my experience many of the controls in ECU's are sinking which means they are switching to ground when they are turning a component on. This is in contrast to sourcing which is where they provide +12V to an activated output. For most electronic design, sinking is simpler and more robust, BUT I've seen ECU's that have both. Just double check everything, and then triple check it again.

Revival Cycles What I've been doing on my wiring diagram is edit it in photoshop with layers. First I marked out all of the connections with their component layers. Then, I went through and eliminated the lighting and power relays so they're always on. Now I'm going through and running those positive side wires to the m-unit. The hard part will be figuring out which connections on the ECU are okay to run the 15 amp AUX to safely. Really should have used a multimeter to check the draw on those circuits BEFORE cutting the harness to pieces. :|

That sounds like a good method for reworking a wire diagram. And it must be nice to be able to turn off a layer or two so you can see the circuits clearly. For ECU fuses you can also trace the circuits back to the fuses that had been protecting the ECU using the original diagram, then if that fuse is greater than 15 amps, you are good to go, but if its less you could consider adding a fuse just for the ECU. But also remember fuses don't protect devices from damage, fuses are there to protect the wires when components fail. So really the fuse should be sized based on the wires that are feeding the components.

I cannot imagine that removing the turn signals would have any affect on the running performance of the engine. There might be a chance that what you are hearing is a rattle due to something being loose after removing the signals. But electrically they are un-related. It is very unlikely that removing the signals caused an issue with the stator.

Once blinkers plugged back in it stops. Disconnect it starts immediately. Nothing is loose. Shop around here said could be stator. And found a forum about also saying stator or electric on these Yamahas