I'll do one with the engine running tommow.��
From process of elimination its seems to be getting closer to a fueling / balance scenario
As Puk said if youve got wear on your throttle bodys that could give you the problem
what year is your bike
I'm sure i have a set of throttle bodys in the shed i bought as a backup, you can borrow those if you want to do a swap / comparison test
Edit - i never fitted them, so i dont know what condition theyre in btw
Yes absolutely it would2008... On one throttle body there was a little daylight that was around on one half of the butterfly valve, not much but could this really cause such a rough running issue? And why intermittent if the worn butterfly is there constantly?
Yes absolutely it would
Chances are that when the throttle grip is closed, instead of air being accurately controlled via the idle air bypass circuit through the idle stepper motors, it is flowing uncontrollably around the butterfly plate into the engine. Any wear in the butterfly spindle bushes could exacerbate this as the plate can vary in position when closed.
I dont see why you can only see light around one half of a closed butterfly plate unless either the plate is not centrally fitted on its spindle, or the spindle bushes have worn oval allowing the shaft to drop. Is the light showing above or below the butterfly plate ?
After checking for bush wear/loose butterfly spindle I would be tempted to loosen/remove each screw in turn, apply loctite then refit the screws and try to adjust the butterfly plate to close fully with no light showing before fully nipping up the screws to lock the plate to the spindle centrally.
The butterflies don't fully close, they are held open a few degrees by the throttle stop screw, the ones you are not supposed to fiddle with. AFAIK they are set up on a flow meter and the screws then painted.
I really think you should take it to Steptoe, the summer will be here and gone........just like your cash as time goes on. Not having a go, just want you to get it sorted once and for all rather than shots in the dark.
Agreed wholeheartedly. (posts 122/123).
Thanks I'll ask.