First of all I would like to excuse because my technical knowledge is not that great, so my friend had some issues starting his ducati monster 600, few days ago, although electric starter worked normally, but bike just wouldn't start, occasionally you could hear loud bangs from exhaust, I guess gas got thrown into exhaust and fired there. So we decided to check spark plugs and spark plug on vertical cylinder wasn't giving a spark, but what I don't understand is why when spark plug on horizontal cylinder worked normally but bike still wouldn't start. Is one cylinder not enough to start a bike? We had little argument with my father about this and I want to clear out that, also would appriciate any other opinion what could be wrong with the bike, we didn't look into bike after that, we just assumed it's spark plug.
I had a similar problem on my M600 a couple of years ago. The.bike would run normally and randomly cut into just one cylinder. Sometimes I could stop pull off the plug cap, replace it and all would be fine for a day or two. Eventually the problem got more frequent and starting harder, as one cylinder isn't always enough to get these high compression engines started. Further investigation showed no spark on the vertical cylinder with the plug grounded to the cylinder. Next I removed the plug cap and grounded the HT lead itself and still nothing. Working back from there I checked the coils and igniters. The problem eventually turned out to be the ignition pick ups under the flywheel, inside the left-hand case. You can get cheaper replacements from Electrexworld in the UK and I am sure others too. You'll need to do a bit of soldering but it is fairly straight forward to do. Basically test backwards merhidically from the sparkplugs till you find something wring. Hope this helps you to trace your problem.
My M900 does frequently fire up on just the horizontal cylinder. usually then I remove the vertical plug, clean it and then no problem. I guess I ought to play around with mixtures or plug temperatures, but it doesn't happen often enough to worry me. not sure why your M600 won't run (even if a little lumpy) on just 1 cylinder, though. Maybe it is a problem further back down the system as mentioned above. Pete
It already has the coils and leads done, along with the starter cables. was stored over winter with no trickle charge, heating, or similar, and started very easily (albeit on 1 cylinder). I guess it just needs to be used more so as to burn any build up of crud?? maybe even preventive maintenance by cleaning the plugs more regular? more than happy with the old monster though, and can live with a little foible like plug cleaning on a 24 year old bike.
Surprised it would foul then. Did the second cylinder chime in on its own? May be worth trying iridium?
horizontal fired up fine, ticked over, and would even ride (although very underpowered). probably worth looking at plug choice a bit more at some stage.
Iridium use a larger gap, so give a fatter spark. Your existing plugs would probably tolerate a larger than standard gap too, given the stronger coils
Re: OP post :- wot Samurai said plus don’t forget to include replacing troublesome cylinder's plug lead before tackling pick ups in crankcase. If a plug lead breaks down repeatedly due to proximity or damp then it can be tempted to track along the same course instead of along route to plug (unlikely but easy to rule out). Also connections on igniter and coil alone can be to blame and even when you delve into the crankcase, the leads to the igniters are a bit torturous particularly near the "restraining clamp" and can both short out to earth/between each other or go open-circuit here or at the soldered connectors. Lots of people have covered this in the past and might be worth searching this and other Forums for more clues/help.
This can also be a symptom of a loose alternator nut. Has the engine been making a knocking sound?? If the nut comes loose (not uncommon), the flywheel wobbles and can take out an ignition pick-up
