| Bike Lurching/Surging/Coughing Problem - Help!!
So my 2002 900ss is playing up big time.
It has developed what can only be described as a surge or cough when under power. No other way I can describe it really. Usually, whenever the revs get close to 5,000rpm and above, there is a sudden, short loss of power, then it picks up again. Sometimes this will happen once in a while, every mile or two perhaps. Other times it happens almost constantly.
I've tried to figure out if it happens when hot or cold, doesn't seem to matter. Tried to figure out if it's with full or empty-ish fuel tank, doesn't seem to matter. Tried to figure out if it happens at different rev ranges and usually it is between 5k and 6k rpm, but this morning it was particularly bad and happened all the way from 3,000rpm upwards.
So far I have done the following:
- drained the fuel tank totally. And there was a significant amount of water in the bottom - about 1 inch in the bottom of a 1 litre plastic drink container.
- change the fuel filter. Did both of these at Cadwell on Tuesday. I had 15 trouble free miles on the way home, before the problem started again.
- Changed old spark plugs for new. Fortunatelly my 900ss and my DD bike use the same plugs and I had a spare set.
- Put the standard pipes and airbox back on. The problem was still there, just that the "buck" of the bike didn't seem so bad with the standard pipes on.
All of the above has been to no avail. Problem still happens.
Someone suggested that it could be my potentiometer, but the SS ECU doesn't have one.
I'm supposed to be riding to Normandy on Friday evening for the bank holiday weekend. However, at this stage I'm not sure the bike is up for it. Looks like my weekend could be stuffed.
Any ideas? I guess it's too late to get it into a workshop now, but is there anything else I might try?
Help!  | 
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