Running rough.

[KiwiCol]

I can send you the ecu from my black to try if ya like, just give me a yell & will arrange it.

There couldn't possibly be anything, like a flap of sheepskin, fouling the air intake at times?   It's doing my head in & it's not even my bike!  I really want this solved, n no doubt you do too.

[Eric GSX1400K3]

Hi Kiwifruit, have you checked that the fuel line under the tank isn't being pinched and that the breather hose from the tank that runs down behind the engine is not blocked? This could be causing a vapour lock issue in the tank causing rough running.

[Kiwifruit]

Thank you for that offer Col l may well take you up on it. Have spoken with a couple of blokes involved in the racing world, they say put it on the dyno and try to get it to replicate the problem while the diagnostics are attached to it. I think it could well work as you can run the engine hard, snap the throttle closed and let the revs fall right down at a road speed. That is unlikely to happen before Xmas as the race season is now in full swing.

Eric, thank you for your thoughts. Tank breathing was my first thing to check as it seemed to fix itself when l opened the tank cap. That has changed now and does not work. Lots of things happen when you stop and restart the bike. I'm thinking it was coincidence that when l opened the cap it fixed it. To me the tank never had a vacuum in it. It is my belief that the tank breathes through the camp via a ball bearing that rattles on a seat over the breather hole. Think the hose running down the back of the engine is a drain hose should you overfill it.
So gentlemen the quest continues.