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Runing on one cylinder

Discussion in 'Bling and Appearance' started by thecptn, Jul 27, 2007.

  1. My gt650 decided today that it wants to run on only one piston, she must of got jealous when I visited that Ducati dealership on the weekend :LOL: I have troubleshooted the problem to the rear cylinder, and I am thinking the coil pack has bit the dust, I pluged in a multimeter into the dc spades that go into the coil pack, on idle im getting 2v, and increases as rpms increase, is that a normal voltage range? is it possible for a coil pack to go belly up in only 25,000k?


  2. Edit: - reread the post.

    The reason you would be "seeing" 2 V and up, is that every 1/10th of a second you get a "pulse" of 14.7 volts sent by the CDI unit. it increases in frequency as the revs increase, so the multimeter is getting voltages all over the place, so like a good little instrument, it gives you the average voltage. Good multimeter. *pet*. (you would need an oscilloscope to see it)

    To check the coil, hook the multimeter up to the spade terminals on the coil (the ones you unplugged them from), resistance should be relatively low - maybe 10-20 ohms? Either way, try for the good and suspect coil packs and compare results. Then (from memory), between the plug lead and the frame, again, should not be infinite resistance.

    However, easiest way to check the ignition, pull out a spark plug, or use an old spark plug, plug into lead, let it sit on an earth point, crank, and look to see if it's sparking. if it's not, the issue is the coil.

    It would seem to make sense that the coil would go relatively early, if there was a slight defect in the manufacturing process, failure of various forms can occur. (After all, if it didn't happen, we wouldn't need new car/bike/xbox360 warranties.)
  3. We checked for a spark as your description, no spark, that we could see, we removed the front cylinder lead and just let it run on the rear, wouldnt fire over at all, has to be a dead coil.
  4. It could also be the CDI or your plug lead.

    Swap the coils around, and see if it fires on the rear cylinder.

    Swap the lead and try the same.
  5. Got a second hand coil unit with lead, pluged it in, still the same, took it out and held the plug against the frame, a few sparks jumped... :? I noticed that where is a strong smell of unburned fuel afterwards each time I tried.
  6. My transalp CDI's only last about 20km, then the way they are designed to sit under the seat causes them to get squashed and self destruct.
  7. Fuel smell - probably fuel/air mixture being pumped out of the head with the plug removed. Try a new plug maybe? what happens when you put the front plug on on the back? If it has been not sparking and you've been running it, the plug is probably fuel fouled to buggery. But if the CDI unit is sparking, I'd be tempted to say a downstream problem, from what I've been led to believe, they either work or they don't.
  8. Well I found out what the problem was, the carb manifold leading to the cyclinder head had come off!! :oops: and the front one was about to do the same as well, popped em back in and tigthened it real tight, and good as new!

  9. Heh, well good news! is it a hose-clamp type of assembly?
  10. yeah
  11. Well, more experience to add to the know. and you now have a coil for sale. :p