I have a 2001 V11 Sport here in the UK which gets used occasionally. It has always had a bit of a flat spot between 2500 - 3000rpm which has been a pain when moving slowly in traffic. Recently it started running iintermittently after a long run.
 My local shop replaced the intake rubbers and head gasket (which was weeping very slightly) so valve clearances were done. It still didn’t run quite right and a faulty coil was diagnosed. It ran a lot better after this was fitted but it has increasingly started running on one cylinder from cold and then the RH one would cut in. Now it is only running on one or one and half cylinders most of the time so it suggests that the signal being sent to the coil is at fault rather than the coil itself.
Looking at the plug (which has also been replaced) it is running a lot richer on the RH cylinder than the LH one. Thoughts?
Does suggest not firing on the right, so when it does, it’s rich. The plug could be getting sooted up to the point where it won’t spark any more. Have you tried putting a new plug in? Just to see what happens.
Sparks are down to the ECU I’m afraid but maybe wiring and connectors need looking at. (?)
Have the throttle bodies been balanced? I’m not familiar with the model, but if its got two throttle butterflies and one throttle position sensor if they’re out of sync one side could be rich or lean depending on which way the adjustment is. Would be more noticeable at tickover/low RPM. Â Â
Investigations showed that the HT lead going into the new coil wasn’t a particularly good fit. That at least got it starting properly on two cylinders.
A replacement temp sender improved things further by not having to keep it 2500 - 3 revs to get away from a standstill.
A trip down to Corsa Italiana who then set up the  throttle bodies and gave the whole system a thoroughly going through has got it the best it’s going to be. One cylinder was idling faster than the other but the other cylinder would pick up a lot faster once the twistgrip was moved and thus causing the poor running and hesitancy between 2 - 3000 revs. I’m picking it up tomorrow and hope that it is finally rideable at slow speed.Â
