Hi! Could anyone advise me on where to look / parts to replace... My 900ss misfires on the horiz cylinder the moment there is the slightest rain. It's been like this for years, but as I never ride in the wet with it I wasn't bothered. My 999 (wet use) is in bits, so I need to ensure the the SS is going to be fine for a touring session. Any pointers where to check, the bike itself is in mint condition generally. Thanks! Grant
First thing I would do is check the plug and plug cap; then the HT lead. After that I would consider a coil problem.......My Guzzi used to misfire like mad in foggy and damp weather, but not in actual heavy rain......that was the coils.
If it were to happen again, use a stick to move the HT leads around (to save getting yourself a hefty wallop), if it suddenly chimes in on both cylinders, most likely the lead you just moved has a tiny crack in it, but enough for the spark to arc out where the lead normally sits, to the frame, or engine block, rather than get all the way to the spark plug.
BTW, I only use NGK plugs and caps; those with the rubber seals that fit the plugs and the HT leads. I also use wire core leads.
it's fairly normal for an early belt two valve to short out front plug lead to head in constant downpour of rain and even more likely on a Monster or Elefant. I can remember stopping many times to experiment with plastic bags etc in desperation but finally found that pulling spark plug cap up as far as possible without it falling off was the best solution to get plug body as far away from head casting as possible. If this is the culprit then probably one of the many available ignition damp start sprays might help but not the sort of thing I carry on a journey.
Fully agree with above observations, however from hard won personal experience check the integrity of the ignition pick up wiring gland. Never had an issue with my '92 900ss in the rain, till it went to Dr Desmo following that it would always die in the rain, first onto one cylinder then die completely, took ages to discover it was the ignition pick ups getting soaked as this crucial barrier had been compromised during it's time at Dr Don't know! Fixed it eventually whilst touring in the French Alps, unscrew the gland and run a small bead of silicon sealant around the base and re tighten. Been fine ever since. Suppose I should buy a replacement now after so many years Best of luck with it.
