Hi all I'm trying to diagnose why my 900ss seems to be running unevenly, like on one cylinder. Brief video here - https://www.youtube.com/shorts/lDUMyveQY2A Spark plugs are good, fuel to both, and there is spark on both. I'm now thinking maybe it's the ignition - either the igniters or the coils? I have a spare set of coils from a 95 900ss, but they are different from the standard grey ones, and with MTA plug leads instead of NGK. I was going to swap these over - question I have is are they interchangeable, and would they cause any damage/issues if I were to hook them up? Current Coils =
Simple stuff first, give the battery an hour or two on the charger. Once started can it be revved, or does it still gasp & die?
Yes, simple stuff first. Are leads plugged into the correct ignitors? (Can't quite see your colours in the photo, I got it wrong). Mixture screw setting? Pick-up air gaps? Just a few guesses. Cheers Gaz
Thanks for all the replies Just to answer a few of the questions - Lead connections are all correct (cross checked against another running SS) The carbs settings haven't been touched, but it was running perfectly before layup. Pick up gap was checked previously, as part of an investigation into a separate issue, where the bike will only travel a limited distance before dying and requiring breakdown recovery. Tank has been drained and filled with fresh fuel. The battery is now on charge as it won't even turn over today.
Ignition problems and fuelling problems am can give similar symptoms for info. Does sound like your battery may be ropey for a start. Before you start changing stuff out, check as above and if it still looks like it's ignition, swap the coils round, and then the igniters, to see if the problem moves to the other cylinder. This will diagnose those four components quickly. Checking which cylinder is running by the heat on the exhausts.
Ok, from bad to worse.. Full charge on the battery, and now I get this: https://www.youtube.com/shorts/m16hT5Eg-YQ Swapped the battery out to a known good battery on another SS - same results. So I think we can rule out any battery issues. Also, I now seem to have a massive fuel leak issue, coming from the drain/breather tube on RHS carb bowl. [edit] I've tightened the screw to stop the leak! And while we're at it, let's throw in some dripping oil/fuel mixture from the exhaust manifold on the horizontal cylinder head! See small puddle to the right.
Hey, on that I’d take the plugs out and make sure the engine spins and it’ll blast any fuel out of the cylinders. If it’s still really sluggish turning over with the plugs reinstalled I’d be looking at the starter cables and main earth cable and starter motor. With the roughy running and fuel out of the overflows I’d strip n clean the carbs first before looking at the ignition seeing as it’s obviously firing. Hope this helps
Sounds like muck in the carbs, or possibly a holed float. Strip and clean the carbs and give the floats a shake to see if there is any fuel in one. If it’s really bad you feel the extra weight. My 750 was running, but only just when I got it. I cleaned half the Gobi desert out the carbs when I stripped them.
