I have replaced the offending item and had a very brief test drive - the dead spot on the first inch of throttle travel has gone, its now immediate to rev up and feels very perky.
When the revs fall it no longer undershoots and its idling a little bit higher too - solid idle.
This has made is so much nicer to pull away without sputtering and bogging down.
Points to note:
The the technical instructions some the live electrical feed does not seem to fit to the plenum (unless its one of the main wires at the back which unhook without any fuss.
When you think everything has been undone and want to remove the air take box you will probably find a vent to the sump is still connected at the back underside of the airbox - now this won't come off the airbox like it suggests but instead get a helper to lift the box up and with a torch follow it down to the sump. Squeeze in the clip (similar to the retentions used on the breather pipes up top) and remove at the lower end - easy
My thottle butterflies were quite dirty and there was a hard residue along the lower edge of the butterfly. I cleaned them the best I could using a lint free cloth and a sturdy toothbrush and a can on Wynns carburettor cleaner. To open the butterflies and clean the back of them and inside where they shut pull the actuator rod down and then wedge a piece of wood near the top.
The airbox had quite a bit of oily residue inside, this was cleaned out with some cloths and petrol. The small breather hose to the sump had lots of black bits of gunk come out which couldnt have been helping things.
Since I didn't have the right tool to remove the fixings on the Idle Control Valve (ICV) pipework, I removed it and the other electrical valve its plumbed into and rinsed through with carb cleaner/petrol. A little dirt came out so I think it was worth doing. I had previously been squirting a lot of carb cleaner down the top hose so perhaps that had already cleaned it a bit.
When replacing the throttle actuator switch the screws seem a little soft so pick a good screwdriver and take your time. When replacing the new one remember to remove the green O ring as the new one comes with it already in the switch recess. Make sure the spindle is pushed home firmly. In comparision the switch that came off rotated much more loosely than the new part, it makes me wonder if the other similar switch on the front of the throttle bar could also be wearing. At 38k miles it may need preventative maintainance.
Removing/Installing the special airbox metal clips:
To remove the clips use chanel lock pliers in a wide setting and pinch the clip using the bits that stick up. You are looking to unhook the outer part of the band from the inner bit, it should ping open and hopefully wont fall down
[img]http://zo-d.com/stuff/images/channel-lo ... -s.jpg[img]
First prepare some choice swear words.... lightly grease the rubber pipes which will help seat the airbox on the engine over the lip (if you look inside there is a locating lip which you want to slip into place without snagging. I used a light smear of grease.
With the clips in the starting position (~1cm back from locked, the tab will rest in the notch and be loose on the rubber pipes) rotate the clip around until you can get a the pliers onto the clip and with firm and slow pressure, gently pinch together until the clip snaps into place. Its really easy with those pliars (needlenose ones didnt have the purchase or force to make it easy) however the 4th and 5th one from the front can be tricky, turning the pliars around helped as did accessing from the gap between the metal fuel rail.
I will try and take some photos of the spare clips I bought to show the removal and fastening pliar positions (never needed them but worth buying a few to play with beforehand).
