Ducati Monster Forum

Moto Board => Tech => Topic started by: IRISH on June 02, 2012, 03:00:28 PM

Title: Riding a thumper with vertical cylinder dead.
Post by: IRISH on June 02, 2012, 03:00:28 PM
When starting up, only the front would fire until finally the vertical would roar to life. Happened consistently and all was fine after warm up or furl flow or whatever. But, now the vert won't come to life at all.

Any ideas and or how to trouble shoot?
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: ducpainter on June 02, 2012, 03:36:50 PM
What bike?
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: IRISH on June 02, 2012, 06:38:15 PM
99 monster 750,

30k trouble free miles, garage kept
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: Howie on June 02, 2012, 08:24:46 PM
Got spark on the vertical cylinder?
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: IRISH on June 03, 2012, 08:30:56 AM
New plug, no spark, plenty of battery juice, no visual frays or looseness to the coils.

Appreciate your help and want to trouble shoot myself. I need guidance as to tools and what to test.
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: chris1044 on June 03, 2012, 10:18:33 AM
How are you checking to verify you have no spark?  Plug inserted into wire and then good wire ground from the electrode to cylinder head?  I'd diag like this:

1) Check for spark with a spark tester
2) Ohm out the wire with a DVOM.  If it's open = replace.  Should be very low on resistance - less than say 10 ohms
3) Ohm out the coil with a DVOM (search...specs for both windings should be out there somewhere) - replace if not in spec
4) Verify the coil is being told to fire per the ECU.  I'd do this with an oscilloscope, but you likely don't have access to one.  In that case if you have a good DVOM you may be able to use that. 
5) Verify resistance from ECU pins to coil connector pins
6) If everything else checks out good..there's a dead driver in the ECU.

You'll need a good schematic or someone to tell you which pins at the ECU connectors feed the coil connector as well.


Title: Re: Riding a thumper with vertical cylinder dead.
Post by: Howie on June 03, 2012, 10:20:12 AM
Check the ignition pick ups for resistance.  The wires exit the right side cover towards the front and go to the ignition modules.  The two wire connector is from the module.  You should have 100+5 ohms resistance.  If both pick ups check good the problem is a module, ignition coil or related wiring.  Firs check all connections are good.  Easiest shade tree diagnostics is to swap parts one at a time from the vertical cylinder to the horizontal cylinder.  The part that causes the horizontal cylinder to not fire is the bad part.  You may or may not have a coil and coil wire that are one piece.
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: Howie on June 03, 2012, 10:34:31 AM
Quote from: chris1044 on June 03, 2012, 10:18:33 AM
How are you checking to verify you have no spark?  Plug inserted into wire and then good wire ground from the electrode to cylinder head?  I'd diag like this:

1) Check for spark with a spark tester
2) Ohm out the wire with a DVOM.  If it's open = replace.  Should be very low on resistance - less than say 10 ohms
3) Ohm out the coil with a DVOM (search...specs for both windings should be out there somewhere) - replace if not in spec
4) Verify the coil is being told to fire per the ECU.  I'd do this with an oscilloscope, but you likely don't have access to one.  In that case if you have a good DVOM you may be able to use that. 
5) Verify resistance from ECU pins to coil connector pins
6) If everything else checks out good..there's a dead driver in the ECU.

You'll need a good schematic or someone to tell you which pins at the ECU connectors feed the coil connector as well.




The bike in question is carburated.  Spark plug wires have rather high resistance, usually about 750 ohms per foot.  The resistance on a Ducati ignition wire is in the terminal cap to the spark plug, which is 5K ohms + 10%, wire itself should be close to 0 ohms.

Ohm readings on the coils are 4.5 ohms + 15% from small terminal to small terminal and 13.5K ohms + 20% from the spark plug tower (wire without terminal cap if one piece).
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: wannabfast on June 04, 2012, 10:05:48 AM
i like to swap parts if you have 2 availible, swap the horizontal and vertical coils and if the spark moves, replace coil, if not do the other testing
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: IRISH on June 04, 2012, 06:27:40 PM

If we could just speak probabilities for a moment. Would a failing coil have this sort of history, intermittent performance at start up - then work fine after warm up until all out failure?

What are your thoughts?
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: ducpainter on June 05, 2012, 11:36:09 AM
Quote from: IRISH on June 04, 2012, 06:27:40 PM
If we could just speak probabilities for a moment. Would a failing coil have this sort of history, intermittent performance at start up - then work fine after warm up until all out failure?

What are your thoughts?
A tired plug could do that too.

However you test by the swap method make sure you only swap one item at a time.

That way you'll know which part is at fault.
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: IRISH on June 06, 2012, 04:44:53 AM
Quote from: ducpainter on June 05, 2012, 11:36:09 AM
A tired plug could do that too.

However you test by the swap method make sure you only swap one item at a time.

That way you'll know which part is at fault.

Ordered my manual, swapping parts one at a time this weekend. Thanks guys.
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: IRISH on June 09, 2012, 10:51:27 AM
Here's the diagnosis;

After swapping parts and confirming resistance. ohms  with a multimeter, the culprit seems to be the vert cylinder pick up coil.

Anyone have some experience with changing that out....?
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: Howie on June 09, 2012, 05:46:50 PM
You need to remove the right side side cover.  One screw is behind the clutch slave, so that needs to be removed.  You can leave the hydraulic line on, just don't squeeze the clutch lever.  Keep the side cover screws in order, they are different lengths.  A puller, though not necessary, will make removing the cover easier.  A cheap steering wheel puller will be fine.  Remove the alternator cover (small plate on side cover with two screws).  Install puller.  Remove cover.

You will see the ignition pick ups.  If you buy OEM pick ups they come on a bright shiny new bracket.  You can avoid adjusting the air gap  by transferring the pick ups to the old bracket.  Just in case, the air gap is .7 + .1mm.  You would need a non magnetic feeler gauge to adjust the gap.

Reassemble with TriBond or equivalent, or you can buy a gasket from our sponsor  http://www.ca-cycleworks.com (http://www.ca-cycleworks.com).  The torque on the 5mm. screws is 6 Nm, the 6mm. screws 10 Nm.

If you go here  http://www.ducati.com/services/maintenance/index.do (http://www.ducati.com/services/maintenance/index.do)  you can download the parts catalog for an '01.  It will be close enough to your bike.

You can buy after market pick ups from these folk   http://www.electrexworld.co.uk/acatalog/Online_Catalogue_Pick_up_Coils_160.html (http://www.electrexworld.co.uk/acatalog/Online_Catalogue_Pick_up_Coils_160.html) 
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: beethoven on June 09, 2012, 06:32:51 PM
I had same problem couple of yrs ago. I used electrexworld units and replaced both coils while covers off. No problems since. In Oz Electrexworld units less than half price delivered than original.
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: koko64 on June 09, 2012, 07:20:32 PM
I did the same and replaced both while in there.
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: IRISH on June 10, 2012, 03:38:00 AM
Sounds familiar as I swapped the flywheel a few years back.

Thanks guys, I'll order the parts today and shoot for next weekend while the in-laws are here
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: Howie on June 10, 2012, 04:48:40 AM
Exactly the same, except you change the pick ups while you are in there.
Title: Re: Riding a thumper with vertical cylinder dead.
Post by: IRISH on June 10, 2012, 12:55:38 PM
pulled it all apart to size up the job for parts arrival, admittedly, really just wanted to find a loose wire to one of the pickups. No such luck, it looks as should be but for the ohm reading indicating the failure.

Just doesnt look like a part that would fail..... but cant argue with the deductive analysis and walk thru of Hayes manual.

Title: Re: Riding a thumper with vertical cylinder dead.
Post by: IRISH on July 03, 2012, 03:23:38 PM
***UPDATE***

Well ladies, I am indebted.

Couldnt have done it without your help, I just pieced it back together this afternoon and she fired right up. Although electric has always been a weak point for me, your direction proved infallible and did it all WAAYYYY under budget. Tools and parts (off ebay) left me with a total cost $85.

Title: Re: Riding a thumper with vertical cylinder dead.
Post by: wannabfast on July 03, 2012, 04:51:45 PM
Quote from: IRISH on July 03, 2012, 03:23:38 PM
***UPDATE***

Well ladies, I am indebted.

Couldnt have done it without your help, I just pieced it back together this afternoon and she fired right up. Although electric has always been a weak point for me, your direction proved infallible and did it all WAAYYYY under budget. Tools and parts (off ebay) left me with a total cost $85.



NICE!!!! go make the beasts with two backsing!!!