m-Unit Blue on 750 slingshot

[SlingshotmS]

Hi,

I'm about to install an m-unit to my gsxr 750 -88 and mocked up a wire diagram. Can someone tell me if it looks alright regarding the ignition and charging? In case the picture is to big to see I'll describe below.

Two wires from alternator, one giving rectified current to battery+ via main fuse, the other recieving (key on) current from the ignition output on the m-unit into the alternator.

One wire from (key on) Ignition on the m-unit, divides to 4 connections, one to each coil and one to the ignitor/cdi, and then also one to the alternator as mentioned above.

One wire from battery+ (spliced, so essentially same wire that goes from alternator to battery+) to starter selenoid/relay, powering the starter if path is open (if i push start). Then one wire from that same connection point in the relay (the connection recieving power from battery+) to the "Bat"-terminal on the m-unit, giving the m-Unit power.

Am I on the right path here? Or did i miss something regarding ignition, charging, starter and power to the m-unit?

 

 

Edited September 17, 2019 by SlingshotmS
spelling and bad description

[Gixer1460]

Looks / sounds about right to me, although one change i'd make is to lose the 'main fuse' between battery and alternator. If it pops, you wouldn't know it until the battery dies and running an alternator without a battery connected really doesn't do them any good. If you want a 'single main fuse' stick it in the line between ign. switch and the fusebox / M Unit so it kill everything - as it should.

[Askamaskinservice]

Welcome to OSS, an introduction would be nice.

And pictures.

[SlingshotmS]

Thank you for the input and the welcome! Sounds very reasonable about the main fuse location, but at the same time motogadget writes "Just make sure the main fuse is between the reg/reg (or alternator in our case) and the battery". Althou cutting the ignition will indeed kill the bike and thereby stop the alternator from overcharging so I guess that makes sense. Just wonder why motogadget says to put it between the reg/rec and battery...

An introduction, of course! Michael 29yo from Stockholm, Swe. Currently have two bikes, one sv1000s with a usd fork and yoshi exhaust, and my project bike (mentioned above) that i'm just about to start working on. I'm going for endurance fairings w single headlight, solo seat, usd fork, swingarm swap and 5,5 rear wheel, m-unit, yoshi exhaust and a nice rk-paint scheme (have you seen michael viennes/championship cycles bike? thats pretty much the direction i'm heading). I'm still waiting for the cellar/soon to be mini garage in the apartment building to be cleared out before i can actually start working on it (probably 2-3 weeks) so at the moment i'm just spending money on parts, making plans and riding it as much as i can!

Step two for the project (at least one year in the future) is to do an 1127 or b12 engine swap. But as for now the engine runs very good so it's not prio.

 

 

 

Edited September 17, 2019 by SlingshotmS
nobody cares about the sv so deleted that pic, hehe..

[Alexious]

Hello, 

Did you had any luck installing the m-unit? Did you use the drawing, as shown?  I'm interested to how you connected the orange cable from the altenator. 

 

Thabk you

[SlingshotmS]

Took the entire bike apart and will mount a 1127 engine tomorrow and start putting it all together, never bothered to install the M-unit when i had the 750 in it. But the wire diagram I posted will work for sure! The alternator in these old gixxers need "key on power" to function, so tbe orange wire should be connected to Aux 1 or Aux 2, and then you have to set the output (when you do the configurations for the M-unit) to "Key on power". Hope it helps! 

[Alexious]

Thank you very much for your quick and comprehensive reply, one last thing if I may.. Could you please send me the diagram in the original size/format? When I try to zoom in to look at coil cables and their color codes it's just a blur.. 

Greetings from the Netherlands 

Alex

[SlingshotmS]

27 minutes ago, Alexious said:

Thank you very much for your quick and comprehensive reply, one last thing if I may.. Could you please send me the diagram in the original size/format? When I try to zoom in to look at coil cables and their color codes it's just a blur.. 

Greetings from the Netherlands 

Alex

Just sent you a pm! Respond with your email if it doesnt work/if its blurry  

[Danger_Russ]

Any update on this? Very interested in this as I am contemplating doing the same unit to my 88' 750 

 

 

Cheers

[smudge]

Hi I am using a m unit on my slabie streetfighter this is my wiring diagram I used , m unit is great piece of kit but the side stand function only cuts the power to the starter not the ignition so I spliced in the relay/ diode set up from an old bandit loom, hope this helps.

[Danger_Russ]

19 hours ago, smudge said:

Hi I am using a m unit on my slabie streetfighter this is my wiring diagram I used , m unit is great piece of kit but the side stand function only cuts the power to the starter not the ignition so I spliced in the relay/ diode set up from an old bandit loom, hope this helps.

 

Thank you it does!!! I may call upon you once I get more in depth with it.

[skunkworks]

so after doing battle with an assortment of Eblag harness's I think im at the point of starting from scratch.

my 83 katana has an 88 1127 in it. 

any issues using a dyna  2000 with it , does  it all play well together?

should I base my harness on an 88 1100 wiring diagram?

thanks guys

[davecara]

If you want quick and dirty, use a 600 bandit loom, they’re cheap and plentiful.

Building a harness from scratch isn’t hard, if you want to go that way. Draw it all out and measure everything properly and lay out one circuit at a time following your design.
Just make sure you don’t use any of those shitty blue crimp connectors and don’t solder any joints (there’s a can of worms!)

websites like

www.bikerstoolbox.co.uk

www.Kojaycat.co.uk

will have most of the resources you need

 

 

[Dezza]

1 hour ago, davecara said:

If you want quick and dirty, use a 600 bandit loom, they’re cheap and plentiful.

Building a harness from scratch isn’t hard, if you want to go that way. Draw it all out and measure everything properly and lay out one circuit at a time following your design.
Just make sure you don’t use any of those shitty blue crimp connectors and don’t solder any joints (there’s a can of worms!)

websites like

www.bikerstoolbox.co.uk

www.Kojaycat.co.uk

will have most of the resources you need

 

 

I am curious to know why you don't like soldered joints. I even carefully solder each crimped terminal to go into any block connector to prevent the wire from pulling out. I have found this is especially a problem with new thin wall cable, even though my crimpers are pretty good. Obviously the thicker the wire the less this is of a problem.

[imago]

7 minutes ago, Dezza said:

I am curious to know why you don't like soldered joints. I even carefully solder each crimped terminal to go into any block connector to prevent the wire from pulling out. I have found this is especially a problem with new thin wall cable, even though my crimpers are pretty good. Obviously the thicker the wire the less this is of a problem.

Vibration and corrosion are the two main reasons against using it on automotive stuff. Vibration is an issue because you introduce one small area which is completely rigid into something which is flexible and absorbs vibration everywhere else. Corrosion because unless it gets washed afterwards the acidic flux residue corrodes the copper of the cores and the zinc and metal in connectors.

The other issue is usually the standard of the soldering. 

[davecara]

8 hours ago, Dezza said:

I am curious to know why you don't like soldered joints. I even carefully solder each crimped terminal to go into any block connector to prevent the wire from pulling out. I have found this is especially a problem with new thin wall cable, even though my crimpers are pretty good. Obviously the thicker the wire the less this is of a problem.

 

8 hours ago, imago said:

Vibration and corrosion are the two main reasons against using it on automotive stuff. Vibration is an issue because you introduce one small area which is completely rigid into something which is flexible and absorbs vibration everywhere else. Corrosion because unless it gets washed afterwards the acidic flux residue corrodes the copper of the cores and the zinc and metal in connectors.

The other issue is usually the standard of the soldering. 

Exactly as @imagohas said, an otherwise flexible length of cable now suddenty has a rigid section in it, usually on 20+ year old cable, usually ending up with burnt cable sheathing, which when potentially exposed to oil/fuel and whatever else might be about, isnt a good idea

The response is 100% of the time "I've soldered for years and never had a problem" If thats the case youre either; Lucky, Never noticed a problem or telling porkies (these are the peope who shrink heatshrink down with a fag lighter). Theres no soldered joints in a factory loom and you'll never find one in a correctly and professionally built race bike loom which is arguably the acid test for any wiring job. Soldering PCBs is fine as its a completely inflexible thing but main looms are no go.

And besides, soldering looks shit

[gsxwill]

12 hours ago, davecara said:

 

Exactly as @imagohas said, an otherwise flexible length of cable now suddenty has a rigid section in it, usually on 20+ year old cable, usually ending up with burnt cable sheathing, which when potentially exposed to oil/fuel and whatever else might be about, isnt a good idea

The response is 100% of the time "I've soldered for years and never had a problem" If thats the case youre either; Lucky, Never noticed a problem or telling porkies (these are the peope who shrink heatshrink down with a fag lighter). Theres no soldered joints in a factory loom and you'll never find one in a correctly and professionally built race bike loom which is arguably the acid test for any wiring job. Soldering PCBs is fine as its a completely inflexible thing but main looms are no go.

And besides, soldering looks shit

When explained like that makes perfect sense 

 

[Dezza]

My soldering doesn't look shit as I used to work as a bt engineer for 9 years and if done only resides in loom sections that remain static. And i have a heat gun for shrinkdowns too But yes, I agree. Using a soldered joint in a section of loom that moves (e.g. around the headstock) is asking for trouble as is using a naked flame on the thin shrinkdown suitable for bike looms.

[imago]

59 minutes ago, Dezza said:

My soldering doesn't look shit as I used to work as a bt engineer for 9 years and if done only resides in loom sections that remain static. And i have a heat gun for shrinkdowns too But yes, I agree. Using a soldered joint in a section of loom that moves (e.g. around the headstock) is asking for trouble as is using a naked flame on the thin shrinkdown suitable for bike looms.

It's not about remaining static, it's about vibration. In the same way that handle bars remain static but still vibrate.

The entire loom vibrates in a tiny wave form which constantly changes frequency and pitch. So a solid piece in it causes a 'block' in the wave which stresses the wire/s where they meet the solder and then again on the other side. There's a lot of info on it and studies which have been done worth having a Google. Here for example.

[smudge]

3 hours ago, Dezza said:

My soldering doesn't look shit as I used to work as a bt engineer for 9 years and if done only resides in loom sections that remain static. And i have a heat gun for shrinkdowns too But yes, I agree. Using a soldered joint in a section of loom that moves (e.g. around the headstock) is asking for trouble as is using a naked flame on the thin shrinkdown suitable for bike looms.

Totally agree.

[Suzukian]

Looks clean.  I've helped a group of friends on Hardley Abblesons, if our Japanese bikes have vibrations, those bikes have earthquakes.  I've seen 8" long Header Pin assemblies breake the connecting clip and come apart.

[skunkworks]

so what is a better way of splicing into a wire instead of soldering?

[Gixer1460]

31 minutes ago, skunkworks said:

so what is a better way of splicing into a wire instead of soldering?

Do like the factory - strip wire, insert into brass tube crimp and crimp! Or theres always the blue or red scotchlocs ? ? ?  My - I like solder 

[imago]

Depending on room, where it is etc either decent quality crimp connectors, 2 in 1 out (can also use a 2 pin plug connector). Or remove 10mm of the insulation from the continuous wire where you want the splice, separate the strands into two bunches, strip 20mm from the end of the joining wire, feed it through between the two bunches then wrap it round the two bunches pull it tight enough to close them together again, then continue to wrap until the stripped part runs out and heat shrink over the top.

[skunkworks]

thanks men