Rough Running and Cutting Out

[Tat_Man]

Right then folks..

On riding my new project home last week I was treated to a couple of breakdowns.
Now I was expecting this, the previous owner had warned me and was also keen to know what the problem was once I fixed it.
So, the problem.. It's running rough, very lumpy below 2500. It coughs, Backfires and cuts out when throttled off.

I have spotted something I think may be causing this (check out the kink) but I would like some opinions and advice please.

How does the IACV work please.
(http://s1027.photobucket.com/user/Tat_The_Man/media/kink.jpg.html)
Hopefully the pic is on here, i'm not good at computers!
(http://s1027.photobucket.com/user/Tat_The_Man/media/20140616_125837.jpg.html)

[NortonCharlie]

Looks a lot like a problem to me, cutting the air bleed to one cylinder going to make it run mostly on two = rough and kind of running on 2 sometimes 3 = surging.

The IAVC works by regulating the airflow below the throttle bodies to control idle speed, similar thing as adjusting how far open to hold the throttles on carburetors to adjust idle speed.

[Tat_Man]

Thanks for the info,  It puts my mind at ease a little more now.
I was glad to have seen something amiss on removing the airbox,  but was unsure of exactly what it did.
It's my first fuel injected bike you see.