my 1991 900ss carby has recently been starting on one cylinder, stays on one for about 5 seconds then the other one kicks in, other than that it’s running as it always has, any ideas why it’s begun starting on one?, thanks Mark.
Plugs? Coil? Really don't know the bike but I've had the same with a Guzzi First start of the season it ran on one then the second chimed in, that was just bad gas. This year it would only run on one for an extended period, that was plugs. I'd start with the obvious, plugs then move onto coils, swapping them over if it's possible. Although it may run fine after a while it could be a sign something is on the way out and you may be able to see it by doing soome checks These are obvious so better to wait for somebody who knows them comes on there may be a weak point specific to the bike
I had an intermittent front cylinder cut-out on my Monster front cylinder. Mostly it would be OK but occasionally it would cut out and run on just the back cylinder only, turned out it was a broken wire inside the insulation just at the terminal of the ignition module (wire that energises the coil) so was not always making contact. Odd thing is that, aside from the lack of power it felt and sounded normal when running...
Could be as simple as one carb taking a little time get filled, especially if starting on the side stand
I have as warned, when I got my carby SS that the alternator nut can come loose. It happened and the first symptom for me was dropping onto one cylinder. I’m not saying it is that but I do think it’s a possibility well worth eliminating
Thanks for the replies, I like Nellys answer best as it means I won’t have to do any work!, I’ll wait til it’s stone cold tomorrow and give it a start standing upright (the bike that is, I’ll be marginally crouched).
It seems that it is usually the vertical cylinder that fires first then the horizontal one decides to catch up. My 750 sometimes did it but generally only when the bike was stone cold and in winter time.....the plug was always wet as well. I also discovered it was more likely to do it if it had been on a rear paddock stand which I accept is in contrast to Nelly's comment but if the plug was wet, then I assumed there was enough fuel in the float bowl. In the end I think that maybe the slight tip up at the rear from the paddock stand allowed fuel to trickle down the manifold from the carb. After overhauling the carbs, it seemed to have stopped doing it.
Nelly was right (as usual), I think I was simply forgetting to leave the ignition on for a few seconds prior to pressing the start button to let the pump prime the carbs, anyway yesterday and today I left it for 10 seconds each time before pressing the button and it fired immediately on 2 cylinders both times, getting forgetful in my old age!, cheers Nelly.
