M-unit and Lithio Battery

[Kiiro450]

Hello Folks.

I have a 1985 GS450L that I am rebuilding here as my first bike (project and otherwise). by far the most horrifying thing the previous owner seems to have done with this old girl is wrap the entire thing in electrical tape in an effort to hide the hideous patch jobs, bad connectors, etc. seriously, I pulled off a baseball sized ball of electrical tape to find things like this underneath.

image.png

this is more or less consistent all the way through. Motivation to continue was very low and really only kickstarted once i completed my gearing up safety course (Canadian MSF).

I've since decided to go a different route with this. Instead of fixing this, I've decided to tear it out and do it from scratch. as a "builder" my background is in PC building and I'm a stickler for clean cables so I'm electing to go with the Motogadget M.unit blue (because the basic is sold out so i guess i pay for the one with bluetooth but hey, at least i can set up keyless RFID ignition on my 1985 motorcycle for a fun partytrick right?). This should simplify wiring greatly as the unit is basically plug and play to each component and handles fuzes and relays by itself, and because I'm already working on it I might as well convert to Lithio battery to save space and give me a place in the battery cage to mount the M.unit. (i plan to build on this later replacing lights with LED lights etc).

From what I understand when i convert over to a Lithio bat i need to get a bat with a BMS and new rectifier as they run on different voltages and are sensitive to overvolting.

has anybody done this before and have any experience? anything I should look out for or any particular product you would recommend? Is there anything else i might need to replace in this upgrade?

am I a monster for using a more "modern" solution? I'm probably going to hold on to the old harness and all components incase i sell it and somebody wants to restore it.

[ukjules]

Does the bike actually go ? run ?
Or is it a 'out of hedge wreck' ?
I always like to get bikes going or as near as damn it and assess where it's at before starting a project. It current status.
I then get it mechanically perfect and and end up never restoring it ....

I am sure someone will come up with electrical advice. Way beyond me what you write and suggest doing. I'd say the RR wires you show aren't that bad ?

An interesting project if you are a electric wizard !
Very interesting but do keep the old loom as you say.
Good luck and report on here !

[Kiiro450]

Thanks for the follow up UKJules,

the answer to that is a bit long winded, I apologize and bear with me.

I got into this whole thing because a year ago i made the decision that I want to move away from Canada. I'm mid 30's, single, don't really have much tethering me here, and even with a good "well paying" job the prospect of home ownership is a pipe dream. I came to this realization when i was living in nova scotia. if I'm going to struggle I might as well do it in an interesting country. naturally one of the easiest ways to do that is to teach English so i got my certificate to do so and kind of fell in love with it. I figured it i was going to be teaching english in a foreign country it probably land me somewhere in southeast Asia. Japan, South Korea, Vietnam, Thailand, some place like that. I reasoned that If i were to move to a place like that I would want to know how to ride a motorcycle (or moped, etc), as well as how to fix one myself (think a good mechanic is hard to find when they speak your language, imagine when you are the foreigner)

I spent $1200 CAD on the bike. I have no idea if I was hosed on that deal to be truthful, but I thought it through and reasoned that even if I was ripped off, for my purposed, it was worth it. It was a project bike I could work on and if i got it running then it was a learning bike i could sell before moving abroad in a year or two's time. If i didn't get it running then at least it wasn't an already running bike that I ruined.

the bike came to me with the head gasket cover off and a few of the bolts required to put it on stripped. the previous owner (lets call him PO) bought it from another guy (call him AG) and tinkered with it before selling it. my guess is PO was out of his depth and realized that he basically did one thing, cocked it up, and didn't want to put in the work to fix it going forward. AG whom he bought it from was restoring the bike with the intent to turn it into a scrambler but fell on hard times and his wife made him sell it. PO I think was an idiot, AG I think was probably a good mechanic (with no patience for wiring, which... fair).

I started by basically tearing it down. I'm going down to the frame and have got it to the point where my next step is taking the crank case off the frame and tearing it down. so far everything beyond the point that PO touched looks like it was recently rebuilt. the carbs were recently cleaned, the head looked cleaned, the valves looked clean, the cylinders walls looked great and the pistons looked recently cleaned to a standard of "good 'nuff for a scrambler project" and the pistons rings looked brand new. there was one nick in one of the pistons but it was minor and not contacting the cylinder sidewall, but i'm looking in to the cost of replacing them regardless. forks could be an issue, they are very stiff but they do compress with the aid of a ratchet strap and spring back. they don't' look visibly bent. rear brake works, i'm going to be inspecting it soon when i take the wheels off. front brake works but drags on the disk a slight bit, i'm going to tear it apart and clean it and see if that fixes it. replace it otherwise. no idea on the starter or any of the electrics. PO stated that everything there worked except the tail light wasn't illuminating. tires are 12 years old so i'm replacing both of them. electrical could be fine, or it could be a money pit, but even if I have to replace everything it's still doable (lithio battery ~$250, Recifier ~$150, Stator ~$100, Ignition coil seems be be about ~50 per, signal generator ~300) even though I hope it's all fine, right?

essentially. If i can get this built under 3k i'll be happy, that's still about 2.5k cheaper than a v-star 250 or 4k cheaper than a Rebel 300 at MSRP (which you won't get from the dealership)

[ukjules]

Good history ! and good on the Asia English teaching in the future.
The bike is now yours and must be saved ! (and stored whilst on travels not sold)

I gota say I would want to hear it running before I tore it down and started spraying or whatever. Others may disagree but it's the way I always do it.

I'd look at the engine first ... sort entirely the stripped bolts / threads and get the engine able to turn over.
infact I'd fix all stripped threads. Get them torqued properly and get it turning over.
By doing that you will test all the components like coils , RR, Stator, Solenoid etc etc.
(you can get an idea if these peripheral components work anyway off or on the bike !)

Forget the new electronics at this stage I'd say!
An AGM battery only and get engine able to turn over.
(I say this however being the worst at electrics but get there in the end )

And then for 200$ spent ride it to Italy .....

- what's the status of the stripped head or head cover bolts ? that's my first task usually when pulling a bike from.a.hedge cleaning and repairing all threads .
an excellent task on a sunny day with a few beers.

[Kiiro450]

oh, i forgot to mention, checked VIN first, no accidents, not stolen. it has 19.5k miles on the odom.

It would have been smart getting that engine repaired and running before tearing it down, I think at the time i decided agianst doing that because I was worried that it had been stored in a shed with the cylinder head cover off. I had a nagging feeling that debris had gotten into the motor through the opening for the cam chain. this likely was a justification for me getting started on it right away.

there are three stripped threads (because why stop at stripping just one) on the cover. I have at this point pulled out all of the valves and springs and left ony the valve guides in there. AG, the guy who was building the scrambler ceracoated the outside of the engine as well as some of the inside of the cylinder head (one of the few things he did that annoyed me, but the matt black finish is kind of nice). so i was planning on giving the whole thing a throrough wash on the outside with a powerwasher, and a good scrubbing on the inside, then tackling the threads first (I have dowel pins on order as well, a few of those got stuck).

I organize everything through a collection of compartmentalized toolboxes, so for instance the cyliander head has a section. each tappet, valve, etc were pulled out, cleaned, very lightly coated with fresh 10w40 oil, and individually packaged together in a baggie before labelled and stored (so i know which valves when to which ports). this method carries through for pretty much everything I do.

I plan to make a "nuts and bolts" order soon where I will order a bunch of the most common hardware on the bike so that I can toss any stripped or stressed threads as i am rebuilding. if you have any insight on common sizes for that I would greatly appreciate it. at frist I wanted to keep it "authentic" with JIS (yup, very first thing I did was get a JIS screwdriver), but i've since come to realize that 38 year old JIS screws aren't exactly the most durable fasteners, so i'm fine with replacing with modern philips.

but anyway, the threads. I have a pack of helicoils from PO, but i'm not taking anything for granted, will verify they are the right size. beyond that I have a drill press so the plan was to verify first (as i always do) that I can use the press to tap it and then apply the helicoils to repair the threads. I will focus on getting that done, the rest of the motor cleaned, cylinders deglazed, pistons possibly replaced, then button the whole thing up and work on getting it to turn over on a simplified circuit with the AGM battery as per your suggestion.

for the wiring I'll make sure to take step by step photos of the process and post them, I think you might find it really useful as this m.unit gadget really does seem to be made for those of us who don't want to faff about with fiddly wires. i've posted a picture below so you can get an idea of how it simplifies the wiring diagram. It includes it's own digitally monitored fuses and flasher relays etc. it's probably not worth it for any bike that has it's harness currently working but for a hedge find it just might be a better option (if a little on the pricey side)

m.unit.jpg

[ukjules]

So the m box is like a central unit that join various components / provide power etc and grounds .
And does this with a pre determined set of rules

I.e. if I wanted the horn to go off every time I put the side stand down it could not be programmed to do that ?

and to make indicators work you just plug in the wires of each indicator to m box ?

[Kiiro450]

essentially. i'm not sure if it's programmable however (for your horn examle) but it is fairly convient. it's worth noting it's a company and they do their best to suck you into their product ecosystem, for instance you can buy a gadget that consolidates all of your handlebar wires into one "m.button" that only needs to run a single wire to the unit etc, but at that point it comes down to how much money you want to put into convenience.

that being said

It has 10 digitally monitored circuits that switch off if there is a fault. if the fault is resolved they switch back on agian.
has flasher relay, starter relay for magnetic switching starts with up to 30 A switching capacity, hazard lights, etc
it has a diagnostic function for the status of the circuits as well.

if you get thhe blutooth version you can load it up on the app and monitor thigns like the voltages through each circuit, the voltage of the battery, the tempurature of the device, there is an accelerometer that lets you see top speed and the amount of turns etc if you care about that sort of thing (i don't). you can even set it up to monitor your mileage using the speedo signal to give you a schedule of maitenance tasks, approx condition on tires and chains etc (with the obvious caveat of don't rely on a gedget and do a visual inspection regardless). I think it can even add turn signal noise to your earbuds, but that's getting into "party trick" territory.

gadgets you can add to it if you drink the koolaid include the button that simplifies handlebar stuff, an NFC ignition lock, tire pressure monitoring system etc. you know, in case you want to spend $100 to do something that takes 2 min with a $20 guage.

[Who Dat?]

Helped a guy wire an M-unit a few years ago. It was not the Blue version, but seemed to be overly-complex anyway. After getting it all wired and running (not very easily), it seemed to be a bit of a pain to use, as you had to learn a bunch of new routines for operating the various circuits. VERY non-intuitive. Good luck.