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Ok…

Remember what I said way back at the beginning about some “long pages”? I’ve been dreading this one a little. Not because I don’t want to write about it, but because it was a very complex piece of the puzzle and took some pretty significant research, slow bulky brainpower, and sage advice from more sources than I can remember.

The wiring harness.

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I hadn’t started cutting wires yet – just disconnecting. I pulled up the wiring diagram from my Clymer’s manual…and all hope was lost:

Part of the problem is that when I yanked the battery box/air box and rear fender, I also eliminated where a bunch of the relays that control lights, vampire repellant and warp drive lived, not to mention the ignitor module, rectifier and starter relay. I was confident I’d figure out how to relocate everything, but I also wanted to go all LED with my headlight, turn signals and brake light. The more I did research, the more I kept coming back to the Motogadget M-Unit. This thing is remarkable… it’s a digital power distribution/controller/relay replacement that basically takes the place of about 90% of the bulky analog hardware on the bike.

There are currently two options – one is the ‘blue’ (pictured above) and the other is the ‘basic’. ‘Blue’ lets you control and program the device from your phone over bluetooth via an app, but it’s an additional $70. Although I was geeking hard for it, I still had to be budget-conscious and this stupid little box was already going to cost me a bout 1/4 of what I paid for the Savage in the first place. That and I really didn’t need the bluetooth control, honestly. Another -really- cool part of this is that it’s programmable. For example, you can decide if you want to use a set of rear turn signals and a separate brake light, or integrate them and literally use what they call a ‘one-wire’ brake light setup. You can program how you start and kill the bike – with two separate buttons or just one (start with one push, kill with two pushes). You can even set up how your turn signals work. I set mine to do a groovy ‘fade-in/fade-out’ instead of just blinking on and off. Lots of options. Read through section 9 of the user manual to see some options. Hell, read through the whole manual, it’ll really get you excited about the possibilities!

So once that decision was made and the order placed, I had to figure out how I was going to control it. Since it’s all digital, it doesn’t require anywhere near the amount of juice that traditional analog handlebar switches need. You can adapt them to work with the M-Unit by adding some resistors and the like in-line to get the voltage knocked down, but my whole point of doing this was to simplify. The way this thing works best is by using momentary on-off pushbuttons for everything, replacing the old handlebar controls. Motogadget (Berlin) makes some absolutely amaaaazing stuff – I would have loved to have gone for their programmable speedometer and bar-end turn signals, but they is EXPENSIVE. With a capital EXPENSIVE. Maybe next time. Anyway, I still had to order buttons.

The Motogadget buttons, or “moswitches” come in a few configurations – two or three buttons, and various combinations of black and chrome (black ring, chrome buttons, vice versa, or all for each). If I was going to spring for them I wanted to get the black ring/chrome button versions but they were all out of stock. I can be an impatient little punk sometimes so I looked for other options. You can get momentary bike switches on Amazon or eBay, and most custom bike part sites have some varieties that are pretty reasonably priced. There were some considerations though – they needed to be waterproof (IP65 rating) and vibration resistant. That limited the options. Then I found RebelMoto out of Copenhagen. They make these waaaay cool LED-ringed momentary switches that fulfilled the geek need I couldn’t sate with the bluetooth M-Unit. Since I was going for a sorta-steampunk vibe, having the little high-tech lights fulfilled my Blade Runner / Akira / Tron desires, even if just on a tiny scale. Who knows, in the end a couple years from now I may think they look dorky, but for now I was completely sold.

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So they look cool, and even with shipping from Denmark they were a little cheaper. Great. Now I’ve got a brain and controllers, but I still have no clue how I’m supposed to wire this up. I spent HOURS tracing lines in that rat’s nest of a current wiring harness and comparing them to the wiring diagram until I was pretty sure I at least understood how the stock system worked, and was able to wrap my head around about 75% of what I needed to do to build the new harness.

That 25% though, was baffling beyond all reason.

Here’s the deal. The Savage has a decompression solenoid that fires up once upon starting. It slightly opens one of the valves so that big stinkin’ single piston can get moving. Bikes with multiple cylinders rarely have this kind of thing ’cause the pistons are much smaller in comparison and require less ‘oomph’ to get the engine to turn over. Problem I was having though is that there were no diagrams I could find that explained where in the chain this piece would wire into the M-Unit. I debated just getting rid of it, and some folks out there suggested that unless I was constantly riding in sub-40-degree weather it would probably be fine without the solenoid (if the oil is cold and thick, it’s even more important to have that valve open).

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The other piece of the puzzle was the ignition module. On many of the forums, and I believe even in the Clymer manual, they call it a CDI module, and how it integrates into the harness/brain was beyond perplexing.

This is another place where I have to give some shout-outs. The tech support team at Revival Cycles down in Austin have some EXTENSIVE info on wiring up an M-Unit, and they’ve also created some better diagrams and documentation than even Motogadget has for their own products. If you’re going to try M-Unit-ing your bike, definitely check out their YouTube channel, and this video specifically (which is for the older version of the M-Unit, but the basics still apply) and this one that covers the new version. I went back and forth with Jeff down there, asking questions, sending my own diagrams as I attempted to understand the inherent weirdness, and he was always quick to respond as we hammered out a solution. One thing they clued me in on is that the Savage ignition unit IS NOT A CDI. This is kind of important, as there is an entirely different approach you have to take with M-Unit wiring if your bike happens to have one. So, ignore anything you might read that claims the Savage has one. It doesn’t.

Also had a bit of a breakthrough at the same time from ZSteele on the Suzuki Savage forums when I posed the question if anyone had done this on their Savage, and how they sorted the ignition module/decomp solenoid. Here’s the drawing he sent:

At almost the same time, the Revival guys sent me this, with the arrows pointing out where to re-route some of the wiring:

What I -did- know, is that in the above diagram I was eliminating a bunch of stuff that was being replaced by the new hardware. Anything circled in green was going away:

At this point I finally felt like I was actually understanding the situation. Another quick note – in the above drawing, the lower-right corner shows the Starter Relay, and between the two green circles at the top right you’ll see the two 20amp main fuses which were in one of the separate fuse modules in the old harness. One thing I was unclear on was whether or not the M-Unit replaced those fuses internally. It does not, BUT there are newer, better starter solenoids that integrate the fuses. Revival has a kit you can order that includes the new relay, some mounting hardware and a selection of fuses to cover whatever bike you’re building. I sent them this next one to clarify a couple more things:

Just a little bit of back and forth to refine, and I ended up with a final wiring diagram. Compare this to the stock one above and you tell me if it’s worth it. 😉

So, from the stock harness, the ONLY relay I had to keep was the Decompression Controller, which wires between the new starter relay and the start output via the clutch lever position switch. Forgive the lousy version of color coding – the new wire I got for the project didn’t match the existing wires. Just follow the traces to see where things go.

Now, granted, the above diagram doesn’t include any of the lighting or controls, but there’s a reason for that. One super cool thing about the M-Unit is that all of the terminals on the left side of the drawing above are INPUTS, all of the terminals on the right side are OUTPUTS. So where I’m just showing a single “momentary push-button” switch, the exact same wiring will happen for each – the green wire would just go into the appropriate input hole. Another cool thing that Motogadget came up with is the “M-Button”. It’s a pre-programmed mini-brain for the M-Unit.

What this little piece of Teutonic wizardry does is allow you to connect all of the wiring from ALL of your handlebar buttons to the various labeled leads, tuck it all into your handlebar (you -have- to do this as the handlebar itself acts as a shield from electromagnetic interference from the starter system) and run TWO wires back to the M-Unit (green for control, black for ground) instead of the seven or eight it would require otherwise.

Now that I had all that sorted, I grew a spare spine and started cutting the old harness completely off the bike, yanking the old handlebar controls, and going for it.

I had also ordered an LED lamp for the headlight and new torpedo LED turn signals. Before going much farther I did a bench test, and all seemed like it was behaving as prescribed.

First order of business – lots of on-bike soldering and heat-shrinking will ensue. If you’re going to tackle this, invest in a nice variable temp soldering iron, something you can use to hold the wires steady while soldering, a collection of heat-shrink tubing and a decent heat gun. None of this stuff is too crazy expensive, and it will make a huge difference.

Also – GET ONE OF THESE!!! I’ve been using the old stripper/crimper style for my whole life. This damn thing is a friggin’ game-changer!

Next I mounted the M-Unit in the electronics pan by drilling a pair of holes in the pan itself and then using an M5 tap to thread the hole. The M-Unit is a -little- fragile and you’re not supposed to crank it down too hard. I placed a little chunk of the rubber mat I got for the battery and tucked it under for a little cushion. I then began running the necessary wires forward. Even though the M-Button reduces the number of wires going -into- the handlebar, I still needed to run wires for the turn signals, headlight, new speedometer (which also meant splicing into wires to split off speedo indicator lights), brake light, and power to the points and decomp solenoid.

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The first pass at the new harness now looked like this:

That mess on the lower right is all of the control wires hanging out of the handlebar end. You can see the M-Button dangling as well. I had to sort out all the control wires and solder up the momentary switches, and I used a MUCH longer wire run than I would ever need. I literally ran about six feet of wire from every lead on the momentary switches. Reason for this was I needed to have plenty to run into the handlebar, through the tube and out one the same end so I’d be able too then cut each one down to the precise length I’d need to solder up the M-Button and tuck everything back inside. Better to waste a few pennies worth of wire than to have to start over ’cause one was too short. I used my old handgrips to sort out where I needed to drill the wire holes for the switch modules (one hole for each set of leads). I -believe- I used a 1/4″ hole for each, but I honestly can’t remember and I didn’t get any photos of that for some reason. Suffice it to say that behind the two switch modules, there are holes just big enough for the wiring to enter.

The only sucky part of these groovy little LED-ringed switches is that instead of just two wires for each button (output to M-Button and ground), there are FOUR – the two leads I just mentioned, but then another power/ground combo for the LED. It made things VERY tight. I rigged up a little soldering station using an old AppleTV box to hold the button tight while I soldered. NOTE: Those LEDs are -very- sensitive to heat, and you don’t want to hit them with the soldering iron for too long. Don’t ask me how I know this.

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Getting that little bastard and all the wires tucked back into the bar was NOT an easy task. Patience and something between finesse and brute force are required. You definitely don’t want to go to all this work and then sever a wire due to carelessness.

Helpful hint – since I wanted all of the wires to come out of just one side of the handlebar (I chose the clutch handle side), I needed to devise a way of threading the throttle-side wires all the way over. I grabbed a 3′ long chunk of 1/16″ steel rod I had laying around and threaded it all the way through from the clutch end til it stuck out the other side. I then installed the throttle-side module by feeding it’s wires into the installation hole, pushing them out the throttle side bar end. I then wrapped the ends of those wires tight around the end of that steel rod and electrical-taped the hell out of it to hold them tight… Then just went to the other end and pulled them all the way through to the clutch-side. Oh – almost forgot, after I taped those ends up, I went and installed the clutch-side module. I figured it was easier to thread those wires through to the bar end BEFORE I pulled the other wires across. More space to work with. Hope that all makes some kind of sense.

My configuration would be as follows…
Left controller, three buttons: Top – start/kill (green); Middle – brights (blue); Bottom – left turn signal (amber).
Right controller, two buttons: Top – horn (red); Bottom – right turn signal (amber).

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A note about wire gauges, and wire in general. For all of the digital controls, you don’t need to handle much amperage. It’s miniscule – 10 milliamps, and therefore you can use a much thinner gauge than you would for something pulling more current. For all of the in-handlebar stuff I used 24 gauge stranded (all of what you use should be stranded wire on a bike, period). For everything running between the M-Unit and something where control power was needed, I used 18 gauge, and for the heavy-duty stuff (battery to starter relay, relay to starter motor, main ground) I used either 10 gauge or 6 gauge, ’cause now we’re talking about a 20 amp load. All the wire MUST be oil, gas, heat and cold resistant. Remember, some of this stuff connects to the engine, some runs along the spine between the engine and the fuel tank, and other bits basically hang out in nature. Don’t skimp, make sure it’s rated for this kind of use, and don’t use a gauge that’s rated for less current than you’re cramming through it or you’re going to have bad problems when it melts on you.

Here’s a great example from Revival – this is the core wiring diagram for an M-Unit, new starter solenoid/main fuse combo, battery setup. Note the wire gauge/amp reference chart in the top right corner. I know the chart indicates I could have gone with 16 gauge, technically – but I decided to err on the side of ‘spec’ for the Savage. That thicker wire is a BITCH to solder mounting lugs to. You need the heat of the sun.

A perfect segue. Once I had the front-half of the bike mostly well in-hand, I had to start mucking about with the starter circuit. The new starter relay/fuse combo was going to fit into the old existing rear fender mounts that I wasn’t using anymore. The holes actually lined up perfectly, but the threads from the old fender-side of the holes didn’t extend all the way to the underside where I wanted to attach it. I tried tapping from the underside, but there wasn’t enough room for me to get a good angle on it, so I figured I’d just go in from the back.

Le sigh. As you can see in the above pic – something is amiss. I was like a fraction of a millimeter from finishing that side when the tap snapped off in my hand. I tried a bolt extractor bit, and then just plain-old drilling it out. Nope. Taps are made from really well hardened steel and nothing I had made more than the slightest dent. The little hole in the middle of the first photo was after nearly 20 minutes of drilling.

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Harumph.

Ok, but there is a little metal angle iron for support just above it, and with some finagling I was able to drill a couple of holes and mount it there. In the end, this is probably a better spot for it anyways.

I still don’t know where the hell I’m going to locate the Ignitor Module, exactly… but I’ll sort that out later.

There is a LOT more that went into this – I had to get some split-tubing to encase the bulk of the wires, some expandable mesh tubing for the handlebar end stuff that was visible (partly for protection/organization and partly for looks), add some new splices to accommodate little bits that I somehow missed. But, in the end this is where I got:

I’ll talk a bit about the new dashboard on the fuel tank and replacement of my speedometer in later pages, but I picked up this groovy little speedo from Dime City Cycles.

It wired up quite nicely, simply splicing the wires for the turn signal and bright indicator. I left the oil light disconnected as I don’t have a sensor on this bike, and wired up the neutral as well. The first two worked brilliantly, in fact the turn signal indicator flashes with the same fade-in/fade-out pulse I programmed into the M Unit. But the neutral indicator didn’t work.

I spent a fair bit of time trying to troubleshoot using the wiring diagram. All seemed right, so the only options were that 1) my switch was bad, 2) somehow my wiring was bad, or 3) the gearbox was hosed and I couldn’t actually shift into neutral. Weird to hope for #2 as the least of all evils.

Turns out, it was indeed #2. So follow me here, you’ll see the error of my ways. My brain was thinking of the neutral sensor in the engine as a switch (well, which it is, more or less) and my brain thinks of a switch as something that power runs FROM, to the indicator light, then to ground. Which is true – except I did it backwards. The way it needs to work is that power comes FROM the M Unit, goes THROUGH the speedo indicator, then GROUNDS inside the engine at the switch. Somehow after all that work I did getting the wiring diagram right I managed to miss the ‘chassis ground’ symbol on the neutral switch. Le sigh.

So I reversed the wiring to the right way, turned the power on and got a lovely glowing neutral indicator. Hell yes.

I grabbed a hunk of cardboard and rigged up a temporary place to mount the ignition switch near it’s original location, turned on the power and tried the start button to see if my labors bore fruit.

The snapping of the decompression solenoid was music to my ears. I finished wiring up the starter relay and routed power to the starter motor and points:

This whole process was grueling, frustrating as hell, strangely zen-like, and ultimately one of my most satisfying of moments. I can’t tell you how exhilarating it was when the bastard actually cranked. Up to this point I had no idea if the motor would even turn.

Let the revels begin! Tomorrow may bring dire dread and disaster, but tonight, we celebrate!

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