I am not getting a spark from the horizontal cylinder of my ST4S, I checked the plug in the plug cap of the vertical cylinder and got a spark so the plug is working. My next guess is the coil, but how do I check it? I don't want to just throw parts at the bike and hope for the best! Also do the HT leads to the plug caps come out or are they an integral part of the coil, I don’t want to try taking them out in case I break the whole coil assembly. Finally are the ST4S coils the same as the 996 coils or are they specific to the model?
I think they are std spec on most of the 4 valvers, if you'd been closer I could have lent you one. There probably is an ohm spec somewhere, hopefully Denzil will pick up this thread or I will find it for you. Keith's idea above is a good one.
I was thinking along those lines myself, but was thinking of just swapping over the LT leads to see if the problem switches to the other cylinder. Like I said I'm not sure if you can just unscrew th HT leads like on the older type coils or whether they are integral. I would still like to satisfy myself that the coil is the issue, so being able to test it would be helpful. I'm pretty sure I could check resistance but where do I connect the multimeter and what should it be?
plugleads are seperate items - Magnecor do an excellent (if expensive) uprated replacement. The standard OEM item was a bought in part from Fiat (std on a Lancia Integrale of the day but don't ask me the lead length) The front lead is the most likely to break down due to it's environment plus it's contorted route past the water rad.
