Hello all, Ive owned my 998s for more than 10 years and love it but over the last few years ive noticed the vertical cyclinder does not fire correctly around the 3000rpm with no load. When coasting along in 2nd 3rd 4th etc doing around 25 - 45 mph the bike is like a kangaroo ( like runng on 1.5 cyclinders) I know its the vertical cyclinder because ive taken the HT lead off at these revs and there is little difference in the miss fire sound weres if i remove the horizontal HT lead the engine cuts out. Ive taken it to Ducati but return the same . In brief ive changed coils over with no difference change HT leads, CPS , plugs checked TPS , new ecu , value clearances checked and adjusted , new injectors . When you open the throttle it pulls well and fires normal on both its just cruising unloaded speed it has this intermittent fire, definitely vertical cyclinder and seems to get worse when fully warmed up any help much appreciated Anthony
Yes i had this done / checked last October , was told 2 were out but made no difference to this strange mis fire
air fuel ratio....... if its a misfire its electric or fuel... so if the AFR goes really weak that will give some sort of indication..besides checking the AFR across the whole rev range might help. Dyno is the answer!
They could also run the ignition pick up off of the problem cylinder to see what happens there too... BSD peterborough!
Thank you all for help never thought of dyno and ignition pick up will look into this after this coronavirus, will ring BSD thanks again
Just a thought, if it is the fuel / air ratio thats the problem how do they adjust that if its not a plug in ecu, would i be going down the dyno jet route. It is a definite miss fire or fuel starvation. You can hold the revs at 3k and hear the intermittent beat just like a breaking down HT lead .
No I took it to a place last year and they said that and so had it replaced still the same .i did forget to mark it thro so only have there word . It was replaced with a used one !!!!! Was not given old one back . Live and learn .
