Ignition Control Unit details

[Roger Chatterton]

Please, can anyone (Rob?!) tell me what the connections are for the
7 pins on the ICU? I am mid way through installing a Boyer Micro Digital
to my twin plugged 100 GS. However, as existing Dynatek coils etc are not standard
BMW bits, the wiring is bit confusing. Too many black cables!
Also - no indication on the Dynateks as to +15 and "-" connectors! Maybe it
doesn't matter?
Rob - it was all your suggestion...!!!!

 

[Rob Farmer]

You could just leave the ECU in place or unplug it.

You don't need the Boyers fused wire on BMW's. In fact if you use it the bike wont stop when you kill the ignition.

Two cores to Boyer ignition pickup should be obvious.

Brown wire goes to ground

Black wire goes to the negative of your coils.

The other core (colour not indicated) goes to the positive side of your coil that should have the live from your ignition wire to it (the Green/Blue wire) .

http://www.boyerbransden.com/pdf/KIT00097__BOX00040_.pdf

Are your coils in series or parallel? The Dynatek coils probably have the primary and secondary windings separate so won't have a +ve and negative markings. The BMW coils have a common connection on the windings so the polarity matters.

For reference the pins on the BMW ECU are
Starting from the right hand side when looking at the ECU.

Pin 1 - Black wire goes to the ignition coil and links to the rev meter
Pin 2 - Brown wire is Vehicle Earth
Pin 3 - Brown wire (ground) for Hall effect sensor
Pin 4 - Green/Blue wire links to the vehicle ignition switch (+ve connection)
Pin 5 - Green/Yellow - Ignition Hall sensor +ve
Pin 6 - Switch signal from hall sensor
Pin 7 - Tacho (not Used for this application)

 

[Roger Chatterton]

Many thanks Rob - knew you'd have the info ! I'll leave the redundant ICU in place just in case I need to revert back to standard ignition.
Yes, the little loom of 2 cables to the BB modified beancan are very obvious and no probs there.
Coils are in series.

You don't need the Boyers fused wire on BMW's. In fact if you use it the bike wont stop when you kill the ignition.
There is no fused wire on my loom from BB -or do you mean an existing BMW wire ?

My problem is that the BB Kit is fine, and pretty straight forward, but the existing wiring on my twin plugged PD is a bit confusing. Work was done before I purchased the bike, by Andrew Sexton.

My confusion is with the black wire I need to remove, and replace with the Black wire in the BB loom. Brown is no prob.,-that as you say, is the ground,

the green I think links on the coil terminal to the existing green (from the ignition switch ?).

The problem is which black wire I remove - there is a black wire joining the 2 Dynatek coils in series, ( so it won't be that one ), one black that goes to the tacho, ( so doubt it's that one either!), but NO idents on the coils themselves, so I can't be certain which is the equivalent of BMW's "+15" and "- " terminal, so makes it confusing !

The wire I need to remove ( and replace with the BB black) is, I think one that comes from the ICU unit, hence my request for details of the multi-pin connector idents.

So apart from that, and another problem that took Dave and I a couple of hours of head scratching, ( if you accidentally remove the live wire to the starter solenoid, ALL power to the bike disappears, apart from side lights, and stop light ....!) - well you always learn something new !

Cheers Rob - see I did listen to your advice in that cafe in Belgium!!!

 

[Rob Farmer]

The Microdigital units I've seen all had a fused wire thats marked for connection to the battery. I haven't fitted one for at least two years so they may have changed the wiring slightly. It was a little disconceting to turn the bike off with the ignition and/or the kill switch and have it keep running.

Did you buy Microdigital with the twin plug curve?

 

[Roger Chatterton]

Hi Rob,
yes, I got the specific Twin Plug Micro Digital direct from BB. There is no fused wire for connection to the battery. The Red box takes its power from the green ignition/kill switch source wire. Presume this is a later mod to the version you've used ?

 

[Roger Chatterton]

Thanks for all the detailed info Rob- will be fitting
/wiring on Friday, so all will become cear.
Tried to find info direct from Dynatek website
re coil polarity(or not!), and nothing useful.
Your info is much better!
Cheers Rob
Are you going to NEC Show? We will be there on Wed 27th
all being well.

 

[Roger Chatterton]

Well, after a bit of thinking and following the wiring diagrams, tracing wiring, crimping up a couple of jumper leads and some logical deductions, I have installed the BB Micro Digital system - also thanks to Rob for his valued input.

Installation would normally be very straightforward I'm sure, but as my bike already had Dynatek coils, it was less so- the way they were wired up was not immediately obvious ( done by Andrew Sexton for previous owner). Anyhow all done, and engine finally fired up, timing adjusted to what I hope is about 3 or 4 degrees retarded ( on the assumption of 2mm per 1 degree of retard), and was looking forward to an interesting ride home.
Noticed the difference straight away - much smoother , and certainly more responsive on acceleration round the lanes.also, very smooth on de-celeration, which has always been a bit jerky, no matter how often I adjusted the slack on the throttle cables.
On the motorway, bike sat very happily at around 85 - 90 mph, and still had some ooomph left, which I didn't test, as it was getting gloomy and rainy. However, certainly no problem maintaining that as a happy cruising speed. In traffic , and through town, the tickover needs adjusting ( didn't do that at time of re-timing the bike as it wasn't fully warmed up), but again, no snatch, and way better. It then started to rain very heavily, and I was hoping my wiring was up to scratch, and it was indeed a real test of the system, and all seems well so far. Also nice not to have the worry of those bob-weights getting sticky; but in fairness to BMW, when you do take a beancan apart, everything in there is remarkably well made and engineered, and you begin to understand why they cost so much, but they do need cleaning and greasing on the spring pivots.

So, in conclusion, well worth the time and effort so far, and will fine tune things when I have a dry day and a warm bike ! Also should add that Boyer Bransden (I bought direct from them) were most helpful with a couple of queries I had concerning installing the rotor and stator in the beancan- they even sent me an alternative stator to try as I was having a problem getting it to sit properly level.

Just thought I'd make my conclusions, as it might help anyone on here who might be thinking of making this conversion.