I think my DMC/2 has gone bing...

C

cwis

Full member
Hi all,

Was off to a bike rally on Saturday, had the bitza all packed up and it refused to start.

On investigation, I've got the following.

DMC on position A (normal running) no sparks on either channel.

DMC on position 1 (test) I get a spark on one channel (outer cylinders).

Swap the pick up wires, I still get a spark on the same channel. (Outer cylinders)
Swap the coil wires, and I get a spark on the inner cylinder.

From this I'm seeing that the pickups, coils and HT leads are fine, leaving me with either an issue with the DMC box, or the trigger wires from the multiconnector under the back of the tank to the DMC unit.

Anything else I can check? Anyone in Bucks have a DMC I can plug in to eliminate my box once and for all?

Shame - it was a nice ride - took the BMW in the end.

Here she is all packed up and ready to go:

27758a66.jpg
 
From this I'm seeing that the pickups, coils and HT leads are fine, leaving me with either an issue with the DMC box, or the trigger wires from the multiconnector under the back of the tank to the DMC unit.
Click to expand...

From what you have described, I'm not sure this is true.  To check the DMC box itself, you can loop the blue & yellow wires (terminals 1 & 2 on the DMC) and that should give you a spark every second on the grounded plugs with the switch set to position 1 & ignition on.

See http://www.laverdaforum.com/forum/index.php?topic=85643.msg216074#msg216074
 
Ah ha!

Thanks Rob - I'll try this tomorrow night and report back.

Chris

Rob said:
From this I'm seeing that the pickups, coils and HT leads are fine, leaving me with either an issue with the DMC box, or the trigger wires from the multiconnector under the back of the tank to the DMC unit.
Click to expand...

From what you have described, I'm not sure this is true.  To check the DMC box itself, you can loop the blue & yellow wires (terminals 1 & 2 on the DMC) and that should give you a spark every second on the grounded plugs with the switch set to position 1 & ignition on.

See http://www.laverdaforum.com/forum/index.php?topic=85643.msg216074#msg216074
Click to expand...
 
Right!

Blue and yellow wires connected, box set to position 0, nothing. Not a thing. Does this test work with a DMC/2?

So far:

Hall sensors are isolated from the frame and are approx 60 Ohms each and 120 across the pair at the connector behind the tank.

I'm measuring 12.5V at the box with the ignition on. If I remove it and ground the wires from the coils (white or grey) on the box's multiconnector I get nice strong sparks.

Coils are fine and 4 Ohms each.

With the box connected (switch position 0) I get sparks on the outer cylinders if I crank the bike. If I wire up the other hall sensor, I still only get sparks on the outer cylinders.

On position A (my normal running position) cranking the bike gives me no sparks at all.

I'm pretty convinced the box is dead - I'd be delighted to be proved wrong!

Chris
 
Set the DMC selector switch to "0" with the blue and yellow wires connected. Ground your spark plugs against the valve cover. Do not let the spark plug wires remain un-grounded.

Power up by turning the ignition on and see it you have continuous sparking at all three plugs. Sounds like the answer is no.

If no, check all your wiring. The DMC may not be getting power or has a poor ground. The units are pretty tough. Could be dead.

Herr Witt's email is: DMC@motowitt.de
 
Thanks Rusty. I tried it connected directly to the battery (earth and power supply) still nothing with the yellow and blue wires connected.

I will email Uwe and see what he thinks - I take it from the other thread he may take a while to reply...

Chris
 
Hi all,

Had a reply from Uwe with another test:

Hi Chris,
 
i need to know, which software has been downloaded to your DMC.
the DMC boxes are all the same but software is different.
in case it is the "LAV1000" then you may run the diagnosis subroutine (position "0" at the switch)
disconnect all pickup wires and then connect the blue wire to +12V battery.-----> continous sparking at the outer spark plugs
and now connect the yellow wire to +12V battery------>continous sparking at the inner spark plug
if this test is ok, have a real close look at your pickups and their wires, they fail time by time.
 
 
with regards
Uwe Witt

Obviously I will be trying this one tonight!

Chris
 
Is this like Regggies and Daves optical pick up? did someone say ?8 or am I wrong (its been known :D)
LJ
 
lemonjelly said:
Is this like Regggies and Daves optical pick up? did someone say ?8 or am I wrong (its been known :D)
LJ
Click to expand...

I'm using the original pickups. I know, I know - Uwe has said it too! You are all right, but in this case it looks like it's not the pickups...

Waiting for the prognosis...
 
Hi all,

Still waiting for  a reply from Uwe - the test results were as follows. I'm guessing bad box, but I'll wait for the expert to confirm:

When I connect the blue wire to the battery, I get continuous sparks, every time. If I swap coil earth connections, I get sparks from the other coil.

When I connect the yellow wire, I either get nothing (most of the time) or I get continuous sparks (one time out of ten, maybe?) It is very intermittent. If I get sparks, they continue until I turn the box off. If I do not, they do not appear until I restart the box (and then only very occasionally).

If I connect the triggers up just after I get sparks from both the yellow and blue wires, when I spin the engine over (position 0) I get sparks on both sides, plus with the box back in position A, I also get sparks.

This happens over very occasionally however - I tried a couple of times to get the spark plugs back in the engine to see if I could get it to run but I had no luck!

If I connect the triggers up when I only get sparks with the blue wire, in position 0 I get sparks on the outside cylinders only, and on position A I get no sparks from either channel.

I have made sure I have good connections for power to the coils (red wires) and earth from the coils (white and grey wires) for this test, and I powered the box directly from the battery.

Chris
 
Hi Stefan

I wiggled the connector and the wires and it didn't seem to affect my symptoms.

Am I right in thinking that I could use small spade connectors to temporarily replace the loom?

Might be worth a go as a check, because the symptoms could point to a broken wire...

Best regards

Chris


1000/3C_Stefan said:
Chris, have you already checked especially the yellow wire down its way trough the multiple spade connector of the box? Some people on the German forum reported about vibration failure near or in the multiple plug.

Regards,
Stefan
Click to expand...
 
Hi all,

Finally managed to find the time to replace the wiring loom to see if it was causing the problem.

Unfortunately not - the intermittent symptoms persisted. I am going to try and speak to Uwe tomorrow if I get time...

Chris
 
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