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I'm still in the learning phase with Ducatis and so, I don't post much. I just search, read, observe and enjoy. That said, I'm looking for some input on a dead cyl situation that I'm having on a 96 SS that I'm very close to resurrecting.

Bike history as far I know: sat on sea dock for months out in the weather and was corroded beyond belief. I've stripped it down to the frame and have re-assembled. It has FCR's which I put on, purchased used but clean and dry. I'm also running a topless airbox with a K&N style filter.

The bike idles on one cylinder- pulling the plug on the H cyl has no effect. When I pick up the RPM with both wires attached, it begins to backfire through the exhaust. With the H cyl plug wire removed it no longer does this. That cylinder is firing some of the time I suppose, and igniting the extra fuel in the pipe. I rode it for the first time yesterday and it was scary. It would randomly fire on two cylinders for a couple of seconds and launch forward violently. The H plug is coming out washed down. The V plug is a bit on the black side- rich.

I've swapped coils, igniters and checked the resistance of the pickup coils, changed plugs, checked compression and valve timing, and cleaned all connections that I can think of. What I haven't done yet: pulled the left side case to check the air gap and ensure the pickup coils are positioned properly, looked too closely at carburation. I popped the bowls when I assembled and all was clean.

Any ideas?

Thanks and cheers.
 

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Dead cylinder

I am not sure if thid applys to your situation but I just purchased a ;99 750SS with a dead H cylinder. The owner said he was riding it pretty hard and bang a dead cylinder. Well the bike would run and idle but as if the cylinder was dead, I checked the spark that was good then check the cam belts and the H cylinder was one tooth off and the belts were slightly loose. This made a believer out of me on belt adjustments and new belts. I reset the timing with new belts and bingo a great running 750.
good luck
 

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before going much further, I would also check cam belt timing and tdc alignment on the cylinders before I did much more cranking.
 

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The timing may be lined now, but was it before? Have you pulled the head? I think you can do that on the H-cylinder without dropping the motor on pre-1999 (but don't quote me on it). I'd check and make sure the timing didn't slip and cause a valve-piston contact... Check for disturbed carbon deposits on the piston and that the valves close completely and in the correct succession... Hope to help... Good luck.
 

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Check for water in your fuel, all it takes is a drop of water to get sucked up into a main fuel jet to block it. Water won't pass thru. I'd drain the fuel tank into a clear container, if there is any water it will sit on the bottom of the container if left over night.
 

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Discussion Starter #7
Check for water in your fuel, all it takes is a drop of water to get sucked up into a main fuel jet to block it. Water won't pass thru. I'd drain the fuel tank into a clear container, if there is any water it will sit on the bottom of the container if left over night.

Fuel is fresh and tank was bone dry when filled. Bike has been inside thru the reassembly. The plug is being washed with fuel so lack of fuel doesn't seem to be it- maybe too much though. I'll be having a closer look tomorrow. I don't think I'm up for pulling the head just yet. I'll check clearances and pickup coil timing first.
 

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i'd be focused on ignition, if all lines up, and there are no clearance issues. I'd do a comp check to be safe, then swap/test ignition from the plug back. I had a similar issue, and it turned out that I had a bad connector at the ignitor. It may seem backwards to go from plug back, but at least that's the "cheap" way lol

j
 

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I'm still in the learning phase with Ducatis and so, I don't post much. I just search, read, observe and enjoy. That said, I'm looking for some input on a dead cyl situation that I'm having on a 96 SS that I'm very close to resurrecting.

Bike history as far I know: sat on sea dock for months out in the weather and was corroded beyond belief. I've stripped it down to the frame and have re-assembled. It has FCR's which I put on, purchased used but clean and dry. I'm also running a topless airbox with a K&N style filter.

The bike idles on one cylinder- pulling the plug on the H cyl has no effect. When I pick up the RPM with both wires attached, it begins to backfire through the exhaust. With the H cyl plug wire removed it no longer does this. That cylinder is firing some of the time I suppose, and igniting the extra fuel in the pipe. I rode it for the first time yesterday and it was scary. It would randomly fire on two cylinders for a couple of seconds and launch forward violently. The H plug is coming out washed down. The V plug is a bit on the black side- rich.

I've swapped coils, igniters and checked the resistance of the pickup coils, changed plugs, checked compression and valve timing, and cleaned all connections that I can think of. What I haven't done yet: pulled the left side case to check the air gap and ensure the pickup coils are positioned properly, looked too closely at carburation. I popped the bowls when I assembled and all was clean.

Any ideas?

Thanks and cheers.
Change your plug wires and make sure they make good contact in the coils. I had the same problem, new wires and ensuring good contact worked for me.
 

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I'm still a firm believer that all backyard mechanics have at least a Leak Down Tester in their toolkit. These things will definitley help find most mechanical woes related to the combustion chamber: bent valves, cracked/broken/worn rings, holed/cracked pistons, cylinder liner problems, leaking gaskets etc. It doesn't make sense to go around in circles guessing what may be wrong when this common mechanics tool will help alleviate some of the guess work. :)

This is SNAPON's most current kit, well worth the money ($299.99) IMHO.

http://buy1.snapon.com/products/diagnostics/eepv309a.asp
 

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I have experienced this problem and in my case there was a break in the wire from the ignition pickup coil. The break wasn't visible as the copper wire itself was broken but the wire insulation was intact. It took forever to trouble shoot this. You can check by measuring the resistence across the contact leads that go from the pickup coil to the ignition module. I think it is 94 ohms but thats a guess. the resistence is listed in a Haynes manual. The soulution was, purchase a new sub harness with pickups. Not a difficult job. recheck the air gaps between the pickups and the trigger on the flywheel
 
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