Hello All,
I have been fighting the battle with the above Darmah and have ended up at a dead end.
Awhile back I rewired my two ign pickups with new teflon wire, had the pickups adjusted per spec (alignment and gap).
The bike ran great for awhile, but now it is acting like it is running on one cylinder only.
The pickup resistance is 209 on the Vert cyl and 215 on the Horz in static mode.
The ignition system coils have been replaced with the new units sold by Bevelheaven and the 1ohm resistors removed.
What I am hoping to do now is just replace the two pickups, and also the two Bosch Ingition modules.
Does anyone know where I can either get reconditioned ones or new?
I've spent a ton of money getting this bike back to working order and now this and I am about to just run this duc over a hill into the Pacific ocean after all this.
Somebody out there must know what can be done?
At the wits end!
900SD Darmah Bosch Ignition Modules and Pickups
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darmahdude
- Cucciolo - the Lil Pup
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MartinMille BANNED
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MartinMille BANNED
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You know Bruceabmartin wrote: Dukes love to run on one cylinder if the carbs need attention.
Bruce
I had the exact same thing happen to me the other day , run the fuel low and the Duc ran on one cylinder refill the tank and all was well, well sort of until I cleaned the little fuel screen at the carby end , but by this stage I had played with the carb settings and I'm now awaiting for my synchronizer to arrive so that I can re-tune them
Ken if you need a set of Ign Modules let me know I have a good working spare set , no pic-ups though as I'm keeping those (to hard to come by these days)
One more suggestion. If it is an ignition problem, swap the electrical plug-ins to the Bosch ignition transducers to see if the spark moves from one cylinder to the other. If you can get a spark from each one the problem lies elsewhere.
New ones are hard to find. I got a used one two years ago from Mdina Italia but it turned out I didn't need it after all. Andrew, the new owner, probably has more - check the website.
Bruce
New ones are hard to find. I got a used one two years ago from Mdina Italia but it turned out I didn't need it after all. Andrew, the new owner, probably has more - check the website.
Bruce
1979 900SS
Fredericton, NB
Canada
Fredericton, NB
Canada
pickup resistance should be 220 Ohm +/- 5%, so they are in tolerance (the vert only just - but I'm not sure how sensitive it is to it).
Here's what I'd do if faced with this problem. Other may have a better idea, or I may have missed something some else will think of.
As suggested earlier - examine your spark at the plugs on both cylinders to see if it is actually a spark problem. If it definitely is, or it may be, then:
the first thing I'd check is your earthing of the ignitor boxes to the frame. You must have good clean contact throught the frame mount point. Be very careful to ensure that all paint has been removed from the contact point. You should be using a star washer to ensure continued good contact.
In my experience, it is very unusual for one of the Bosch ignitor boxes to fail. I've never known it to happen to anyone I know. I'd only pusue this a last course of action and after the following process:
Swap the boxes between vert and horiz to see if the problem moves. If you do this and the problem moves, you know the box is the issue. If the problem stays the same, you're down to the pickup or the coil or the wiring. If the problem goes away, then your issue was probably earthing as described above. Needless to say - in this swapping process - be diligent with earthing.
If you're down to the coil or pickup of wiring, swap the coils (if the HT leads are swapable). If the problem moves, its the coil. Check the resitances of your primary and secondary coil circuits. The stock coils were 4 Ohm +/- 10% and 8800 Ohm +/- 20%. Note the 8800 includes the spark plug cap's built in resistance of 5000 (I think) Ohm. Yours may well be different - check the manufacturers specs.
If it remains the same after the coil swap, you're down to pickups or wiring (or possibly HT lead if you swapped the coils). If the problem goes away, check out your ignition wiring - you may have a loose wire somewhere.
If you still have the same problem on the same cylinder after all that it looks like a pickup issue or a pickup wiring issue or a wiring issue between the coil and the ignitor box.
At this point check the continuity and condition of the wire between the offending coil/ignitor box combination. If that looks OK, then the next step is off with the cover.
One fault that happens with the Bosch pickups is that the metal sensor becomes loose in the plasic casing causing variations in the air gap. The system is extremely sensitive to air gap. Check that the metal sensors are not loose on the intermitent cylinder pickup. I've seen these glued up before when this happens. Dunno how effective that is, others may know.
I don't know of any other tests you can do on the pickup other than the 220 Ohm resistance test. I guess at this point I'd reluctantly stump up for a recon (whilst wondering what i might have missed!!!)
Let us know how you go.
machten.
Here's what I'd do if faced with this problem. Other may have a better idea, or I may have missed something some else will think of.
As suggested earlier - examine your spark at the plugs on both cylinders to see if it is actually a spark problem. If it definitely is, or it may be, then:
the first thing I'd check is your earthing of the ignitor boxes to the frame. You must have good clean contact throught the frame mount point. Be very careful to ensure that all paint has been removed from the contact point. You should be using a star washer to ensure continued good contact.
In my experience, it is very unusual for one of the Bosch ignitor boxes to fail. I've never known it to happen to anyone I know. I'd only pusue this a last course of action and after the following process:
Swap the boxes between vert and horiz to see if the problem moves. If you do this and the problem moves, you know the box is the issue. If the problem stays the same, you're down to the pickup or the coil or the wiring. If the problem goes away, then your issue was probably earthing as described above. Needless to say - in this swapping process - be diligent with earthing.
If you're down to the coil or pickup of wiring, swap the coils (if the HT leads are swapable). If the problem moves, its the coil. Check the resitances of your primary and secondary coil circuits. The stock coils were 4 Ohm +/- 10% and 8800 Ohm +/- 20%. Note the 8800 includes the spark plug cap's built in resistance of 5000 (I think) Ohm. Yours may well be different - check the manufacturers specs.
If it remains the same after the coil swap, you're down to pickups or wiring (or possibly HT lead if you swapped the coils). If the problem goes away, check out your ignition wiring - you may have a loose wire somewhere.
If you still have the same problem on the same cylinder after all that it looks like a pickup issue or a pickup wiring issue or a wiring issue between the coil and the ignitor box.
At this point check the continuity and condition of the wire between the offending coil/ignitor box combination. If that looks OK, then the next step is off with the cover.
One fault that happens with the Bosch pickups is that the metal sensor becomes loose in the plasic casing causing variations in the air gap. The system is extremely sensitive to air gap. Check that the metal sensors are not loose on the intermitent cylinder pickup. I've seen these glued up before when this happens. Dunno how effective that is, others may know.
I don't know of any other tests you can do on the pickup other than the 220 Ohm resistance test. I guess at this point I'd reluctantly stump up for a recon (whilst wondering what i might have missed!!!)
Let us know how you go.
machten.
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darmahdude
- Cucciolo - the Lil Pup
- Posts: 5
- Joined: Fri Jan 02, 2009 7:01 pm
- Location: Santa Barbara, CA
A bit more detail on this Darmah Ignition problem
My current issue with my 79 Darmah 900SD is with the ignition system.
Here is the scenario
What I observe is I can idle OK. The bike will run somewhat OK when I take off, then after a period, it will start to stumble and run like it is on one cylinder. There are obvious misfires and backfires in the exhaust when limping home. Upon return to the garage, the plugs are fouled and wet.
Prior to this latest issue, the bike was running very well. I have put new 40mm del orto's on this bike and had the carbs pretty close to dialed in before this happened. Also, this issue arose after a 200 mile ride to LA and back and the temperature of the day up in the 100 range. The next time I rode the bike after that ride I was able to make it 10 miles when the symptom started and could barely make it home with the bike firing on one cylinder in city traffic, but on freeway I could get it to fire on both. From that night on the problem progressively got worse over the next 3-4 rides and the distance I could drive got shorter and shorter.
Suspects:
Pickup Coils shorting out. I know I wired the pickup coils properly, using the right type of teflon wiring and adding high temp silicon sealant around the pickup terminals themselves. The pickup coil resistance is low on each at 209 and 214 (220 +/- 5%) but nothing says a coil can't short out when the engine gets running. The 209 reading is on the Vert cylinder and it is that cylinder that seems to be the one that stops working.
Ignition Boxes shorting out. one of the ign boxes could be going out when it is heated up. There might be a bad transistor in the timing advance array circuit. If one transistor shorted out timing advance on that cylinder would certainly be affected.
Everything else on the bike electrically has been replaced properly grounded and working as designed. I have added the Dyna Black coils. By trade I am an engineer with plenty of hands on with wiring, grounding, and cabling systems. I am wondering if anyone has a schematic of the Bosch ignition system showing the components that make up the circuit.
Strategy:
I am hoping to find one bosch ign module either used and working or reconditioned or praise God, NEW. I can use this on each cylinder to see if the issue goes away. If the problem isn't corrected, then I can focus my efforts on the pickups themselves which has it's own strategy.
Hope this clears things up a bit more. Trust me I love that damn Darmah and won't give up until I have this girl roaring on the road again. Just need a little help from my friends!
Darmahdude
Here is the scenario
What I observe is I can idle OK. The bike will run somewhat OK when I take off, then after a period, it will start to stumble and run like it is on one cylinder. There are obvious misfires and backfires in the exhaust when limping home. Upon return to the garage, the plugs are fouled and wet.
Prior to this latest issue, the bike was running very well. I have put new 40mm del orto's on this bike and had the carbs pretty close to dialed in before this happened. Also, this issue arose after a 200 mile ride to LA and back and the temperature of the day up in the 100 range. The next time I rode the bike after that ride I was able to make it 10 miles when the symptom started and could barely make it home with the bike firing on one cylinder in city traffic, but on freeway I could get it to fire on both. From that night on the problem progressively got worse over the next 3-4 rides and the distance I could drive got shorter and shorter.
Suspects:
Pickup Coils shorting out. I know I wired the pickup coils properly, using the right type of teflon wiring and adding high temp silicon sealant around the pickup terminals themselves. The pickup coil resistance is low on each at 209 and 214 (220 +/- 5%) but nothing says a coil can't short out when the engine gets running. The 209 reading is on the Vert cylinder and it is that cylinder that seems to be the one that stops working.
Ignition Boxes shorting out. one of the ign boxes could be going out when it is heated up. There might be a bad transistor in the timing advance array circuit. If one transistor shorted out timing advance on that cylinder would certainly be affected.
Everything else on the bike electrically has been replaced properly grounded and working as designed. I have added the Dyna Black coils. By trade I am an engineer with plenty of hands on with wiring, grounding, and cabling systems. I am wondering if anyone has a schematic of the Bosch ignition system showing the components that make up the circuit.
Strategy:
I am hoping to find one bosch ign module either used and working or reconditioned or praise God, NEW. I can use this on each cylinder to see if the issue goes away. If the problem isn't corrected, then I can focus my efforts on the pickups themselves which has it's own strategy.
Hope this clears things up a bit more. Trust me I love that damn Darmah and won't give up until I have this girl roaring on the road again. Just need a little help from my friends!
Darmahdude
Schematic at Page 102 of the manual available on this site here:
http://www.bevelheaven.com/manuals/Darmah_W.pdf
machten
http://www.bevelheaven.com/manuals/Darmah_W.pdf
machten
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BevHevSteve
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- Location: Lafayette, California
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Hi Ken, will you please verify your email address as I am getting a bunch of bounces from folks trying to send you emails through the forum.
Steve Allen (925)798-BEVL[2385] Ride'm, Don't Hide'm
Ducati/Euro Spares -> https://Store.BevelHeaven.com
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darmahdude
- Cucciolo - the Lil Pup
- Posts: 5
- Joined: Fri Jan 02, 2009 7:01 pm
- Location: Santa Barbara, CA
Found the problem
First I would like to say thank you for all the help you guys provided so quickly to this issue.
As it turned out, it was not electrical as was assumed.
Turns out my whacko bipolar landlady decided to hurt me where she knew it would and put some substance (not sure what but looks like sugar) in my gas tank
I cleaned the carbs once when this issue came up and there wasn't that much in the float bowls to make me think of something like vandalism, however, I decided to check again and wow. The bowls were saturated and the substance had carmalized with the gas and clogged everything up.
Drained the gas tank and found a large rubber piece which I can't make out what it is yet, a bolt, and more sugary type substance.
With the carbs cleaned and the tank emptied, the bike works fine.
If I make the assumption that it was indeed just sugar, then I might feel safe that the rest of the top end and bottom did not suffer any damage as I know that myth is not as bad as everyone thinks.
The part that makes me worry is if it is not sugar and this stuff gets into the seals in the valves and all over the engine bottom end, will I have bearing seizures and leaking valve guides down the way.
I plan to do more due diligence on the substance and get it analyzed but for the time being, I at least now know what the problem was.
As for the landlady, I left that place end of Dec and have heard from the gals sister that she is Bi Polar and they would like to see her get help to address her anger issues.
Can anyone recommend a locking gas cap for the Ducati Darmah 79 vintage?
Thank you again for all the great help. I hope I can repay this down the way.
Regards
Ken
As it turned out, it was not electrical as was assumed.
Turns out my whacko bipolar landlady decided to hurt me where she knew it would and put some substance (not sure what but looks like sugar) in my gas tank
I cleaned the carbs once when this issue came up and there wasn't that much in the float bowls to make me think of something like vandalism, however, I decided to check again and wow. The bowls were saturated and the substance had carmalized with the gas and clogged everything up.
Drained the gas tank and found a large rubber piece which I can't make out what it is yet, a bolt, and more sugary type substance.
With the carbs cleaned and the tank emptied, the bike works fine.
If I make the assumption that it was indeed just sugar, then I might feel safe that the rest of the top end and bottom did not suffer any damage as I know that myth is not as bad as everyone thinks.
The part that makes me worry is if it is not sugar and this stuff gets into the seals in the valves and all over the engine bottom end, will I have bearing seizures and leaking valve guides down the way.
I plan to do more due diligence on the substance and get it analyzed but for the time being, I at least now know what the problem was.
As for the landlady, I left that place end of Dec and have heard from the gals sister that she is Bi Polar and they would like to see her get help to address her anger issues.
Can anyone recommend a locking gas cap for the Ducati Darmah 79 vintage?
Thank you again for all the great help. I hope I can repay this down the way.
Regards
Ken
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MartinMille BANNED
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Wow some nice Ladies you guys have over there.
Make sure you pul the plugs out and see if you can have a look at the bore as sugar dose a nasty job on them , what the sugar will do is glaze the bore and eventually the pistons will bind on the brown coating that was burned onto the bore , If it was my bike and I didnt want to pull the top end off, I would get some olive oil and fill the cylinder full and let is sit for a week than turn the engine buy had until the olive oil has turned brown do the same for both bores , bottom end shouldn't be affected from the sugar fuel mix
good luck with it
Make sure you pul the plugs out and see if you can have a look at the bore as sugar dose a nasty job on them , what the sugar will do is glaze the bore and eventually the pistons will bind on the brown coating that was burned onto the bore , If it was my bike and I didnt want to pull the top end off, I would get some olive oil and fill the cylinder full and let is sit for a week than turn the engine buy had until the olive oil has turned brown do the same for both bores , bottom end shouldn't be affected from the sugar fuel mix
good luck with it
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BevHevSteve
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Holy cow Ken....... That is just nuts! I usually have locking gas caps but am out of stock at the moment. Shoot me an email to remind me to let you know when I get more.
Steve Allen (925)798-BEVL[2385] Ride'm, Don't Hide'm
Ducati/Euro Spares -> https://Store.BevelHeaven.com
ya gotta be kidding
Darmahdude, you have my deepest sympathy. Just read your thread today and could`nt d beleive it. Talk about kicking a guy where it hurts. Why is it the innocent little bevels must suffer during these altercations. I rekon best defence is use her own accomodation against her and bring the poor Darmah in from the cold. Not only are they great to ride but made excellent clothes horses, talking points, spare seat when friends drop by and you can do an amazing amount of alloy polishing during commercial breaks!!! Ask me how I know...........