Removing a stuck carb screw

[HazzaBui]

Hi all,


Got a bit of a problem with the bike (again ) - I thought I'd save myself some cash and have a go at changing my cam chain myself (needed doing pretty badly).
I got the chain in ok using the split link method, and that all looks fine.  Problem is, the tensioner is extended out too far for me to get the inlet cam back on with the chain on. 
No problem I thought, I'll just reset the tensioner.  So I proceeded to start undoing stuff to take the carbs off (can't quite access the tensioner bolt throught the cars), but now the screw holding the jubilee clip thing, which keeps the carbs on, is stuck.  And to make matters worse, the guy who was helping me has done a nice job of rounding off the head, so can't get any purchase on it.
I did try an impact driver to get it out, but it just spun the clip around the carb, and now it's at the wrong angle.  It's for cylinder 3, so access isn't ideal.


tl;dr the screw holding the carb clip thing is seized and threaded


So, any suggestions from anyone on how to get the bastard out? 


Thanks in advance!
Harry

[His Dudeness]

If you can get a vice grips or a clamp around the clip and squeeze it together it will take the pressure off the screw head and it should turn easier. If that doesn't work you might have to drill the head off the screw.

[Kentish]

Have you taken the other 3 off? Forget drilling in there, impossible due to the location, take the other 3 off then you should be able to turn the carbs upwards u might just have to prize it as you try and remove the carbs ur have to buy another clamp though