No seriously, I actually headbutted the wall

Ever since doing the CCT's my bike wont run properly.
Gutless, has a weird kinda 'chuggy' feeling and just backfires like crazy. Also its impossible to ride at low revs, it just wants to cut out all the time which makes it exceedingly dangerous to ride (if your stupid enough to try...)
Carbs are fine, hoses are fine, fresh fuel in tank - all the usual stuff is OK.
And as far as I can see the timing is OK.
I'll admit I'm not really too clued up when it comes to engines.
Just wondering if theres anyone in Norfolk area could come take a peek?