Another failed BNS12 dash

[Bisbonian]

Heading up to Springerville on Friday I met with some very hot weather. As the thermometer topped 109 degrees I noticed that the LCD portion of my dash blanked out. I pulled over and cycled the key and found the LCD came right back on, Cool!

10 minutes later and the dash craps out again.

I found that every time I pulled over and cycled the key that the LCD would come on for varying amounts of time, on occasion instead of just blanking out I would get black lines and symbols as shown in this picture:

This status would hold for varying amounts of time but was always followed by the LCD blanking out. I haven't taken pictures of the blank LCD screen because you can see that on your own bike, just leave the key off.

The next morning I found that the dash worked fine, until the temps rose above about 90 degrees at which point it would blank out again.

Same thing on Sunday riding home.

So I've determined that this seems to now be temperature sensitive, however I've had this bike for going on 3 years now and have never had the dash blank out previously.

I'm reticent to spend the $$$ it would take to purchase a replacement dash from MG as; A, it is expensive and B, replacement BNS12 dashes have not proven to be fail-proof.

For the moment I'm getting ready to mount a bicycle speedometer to the handlebar so that I can at least keep track of the odometer, all the gauges on the dash with dials still work so it's just the odometer I'm missing and all the extra stuff that's shown in the LCD.

My question is, how hooked in to the ECU is the stock dash?

Can I remove the stock dash and then replace it with something like shown in this link?

http://www.kosonorthamerica.com/new/sho ... le_gauges/

I think I could design a dash panel into which one of these could mount and would look pretty good but don't know if this is even feasible.

I ask because there has to be some sort of communication between the stock dash and the ECU because trouble codes are displayed and calculated mileage is shown on the LCD.

Has anyone broken into a stock dash and determined what is causing this problem and whether it can be fixed or is replacement the only option?

 

[Kevin.NZ]

Hi Bisbonian,
I had similar problems with my 07 Breva 1100, and it always happened after the bike was parked up with the hot sun on the dash. Not only did the LCD blank out but the speedo would stick at various places on the dial after it did the sweep. Turning the Ign on/off would bring it down to Zero k/hr in 10km steps. A temporary fix was to shade the gauge while parked, ie gloves, helmet or under a tree but in the end a complete replacement dash under warrenty sorted it after the dealer tried in vain to fix it using the Axone. I believe it is impossible to access the inside without destroying the unit. There is a very early thread on someone trying to take one apart but I think he broke the needles trying to pull them off the shaft. The odometer readings are stored in the dash not the ECU and Ive had no problems with the new unit.
Kevin

 

[Brian UK]

There are two data connections between the dash and the ECU.

 

[Rafael]

If this only occurs in hot weather, then it could be the voltage being choked off by the connectors increased resistance. I would clean the connectors with Caig DeoxIT D5, that should increase the conductivity of the connections. Its worth a try for just a few $$.

I used the stuff on the starter solenoid connection, it made a noticeable difference - no more of those click, click non starts.

 

[Bisbonian]

If this only occurs in hot weather, then it could be the voltage being choked off by the connectors increased resistance. I would clean the connectors with Caig DeoxIT D5, that should increase the conductivity of the connections. Its worth a try for just a few $$.

I used the stuff on the starter solenoid connection, it made a noticeable difference - no more of those click, click non starts.

You're right, it is worth a try.

 

[Mi_ka]

There are two data connections between the dash and the ECU.

I *think* that the dashboard informs the ECU of the environment air temperature so it is not just a passive unit regarding running engine management.

 

[Bisbonian]

There are two data connections between the dash and the ECU.

I *think* that the dashboard informs the ECU of the environment air temperature so it is not just a passive unit regarding running engine management.

That's what I really want to know, does the dash have a purpose with regard to the functioning of the motorcycle other than keeping me advised of what is going on?

If I can safely dump the stock dash unit then I see no reason to keep it.

However I've not read anything concrete as to whether this is actually the case; I was hoping with the knowledge base over here that someone would have some experience with the interaction of ECU and dash.

 

[Mi_ka]

From "Breva11ServiceMan.pdf", page 62 (injection system pages):
"The principal sensors are:
- Engine RPM sensor measures the number of revolutions of the engine and the phase of each cylinder with respect to TDC
-Throttle position sensor: measures the opening angle of the throttle valve
Secondary or correction sensors are:
- Pressure sensor (in dashboard): measures barometric pressure
- Air temperature sensor: measures intake are temperature
- Engine temperature sensor: measures engine temperature"

I suppose the bigger 2V Breva won't be any different.
Post me an email to send it to you.

The dashboard also has connections for its own air temperature and I suppose it could also send these readings digitally to the ECU along the barometric pressure readings but the ECU also has its own air temperature connection at its plug, I suppose to the air box sensor.

 

[Bisbonian]

From "Breva11ServiceMan.pdf", page 62 (injection system pages):
"The principal sensors are:
- Engine RPM sensor measures the number of revolutions of the engine and the phase of each cylinder with respect to TDC
-Throttle position sensor: measures the opening angle of the throttle valve
Secondary or correction sensors are:
- Pressure sensor (in dashboard): measures barometric pressure
- Air temperature sensor: measures intake are temperature
- Engine temperature sensor: measures engine temperature"

I suppose the bigger 2V Breva won't be any different.
Post me an email to send it to you.

The dashboard also has connections for its own air temperature and I suppose it could also send these readings digitally to the ECU along the barometric pressure readings but the ECU also has its own air temperature connection at its plug, I suppose to the air box sensor.

Well if the barometric sensor is in the instrument panel then I guess it does have an actual function and it's not so easy as just swapping out with a "universal" unit.

The air temperature sensor in the dash is for the ambient temperature as displayed on the LCD portion of the dash, the intake air temperature sensor is mounted on the top of the airbox.

It certainly appears as though I'm at the mercy of MG with regard to the instrument panel. Since the bike functions fine I think I'll just step back to option A which is to mount a bicycle speedometer (with odometer function) to the handlebar so that I can keep track of the miles, if I'm lucky I'll get one with a clock and temperature readout and it will be like the stock LCD never left me.

 

[gsf12man]

My B-11's speedo plays up as Kevin.NZ has detailed—I always cover the gauge cluster with a high-tech shower cap when I get off the bike, as suggested on this forum. It doesn't take it long to heat-soak at all. It comes back to normal after a few miles of riding when that happens (if not covered). Long term, I don't have a good feeling about the cluster, but so far so good. But, these are not the same symptoms you are seeing. Still, might be worth covering it at every stop to see if that does any good.

 

[Mi_ka]

If only I was close enough to try and scramble the data on the ECU-Dash bus over some pizza or so....

As for the dash temperature sensor, if it was me designing the system, since it is already sending barometric data I 'd feed the data of the dash temp sensor to the ECU just for redundancy reasons.

 

[Bisbonian]

Does anyone have any tips for separating the halves of the dash unit?

I have engaged a gentleman who is going to look and see if he can fix what is wrong in the dash but he doesn't want to break anything while taking it apart.

Surely someone has opened this up before?

 

[Rafael]

I have an old semi defective unit, I'll see if I can figure it out then post my findings later; if no one else posts first.

Update:
Okay, spent a few minute mucking around with it. I remembered the PO telling me about installing a strip o tape over a crack on the plastic crystal. So I started there.

I used a smallish slot screwdriver and lifted slipped it in between the chrome trim and the grey plastic body starting at the bottom straight edge. Look into the gap and you will see chrome tabs that snap into the grey body. Pried up the chrome trim little by little going around the perimeter. With few tabs disengaged, the chrome trim came off with a little tug. You'll find small Philips head screw holding the plastic crystal around the perimeter. I stopped there. It appears that the crystal face just lifts off, probably more screws under there to lift the face.

 

[Bisbonian]

I have an old semi defective unit, I'll see if I can figure it out then post my findings later; if no one else posts first.

Update:
Okay, spent a few minute mucking around with it. I remembered the PO telling me about installing a strip o tape over a crack on the plastic crystal. So I started there.

I used a smallish slot screwdriver and lifted slipped it in between the chrome trim and the grey plastic body starting at the bottom straight edge. Look into the gap and you will see chrome tabs that snap into the grey body. Pried up the chrome trim little by little going around the perimeter. With few tabs disengaged, the chrome trim came off with a little tug. You'll find small Philips head screw holding the plastic crystal around the perimeter. I stopped there. It appears that the crystal face just lifts off, probably more screws under there to lift the face.

I'll pass that along, but does the back side come off?

I would think we'd be able to take the back off the dash without having to take the glass off and that sort of stuff.

 

[Rafael]

but does the back side come off?

No, there are no seams/joints or fasteners on the back.