Couple of wee niggles that I need help tracking down, may be the same root cause;
When I first got the bike it wouldn't idle at a constant RPM and needed idle adjuster played with on nearly all the time when stopped. Suspected carb rubbers leaking and spraying easy start confirmed this...which is when I found that the carbs must have been off at some point as the clamps were not done up properly - with this now done the revs stay nice and constant when warmed up...however, there are the following niggles:
1) When slowing down to a halt from motorway speeds, then bike sometimes doesn't even try to idle and cuts out
2) Doesn't idle well when cold
3) There seems to be a dead spot just above idle and then it really picks up revs - make pulling away trickier than it should be
4) Seems very sensitive to backing off the throttle when above 9krpm
Is there still an air leak somewhere; have checked all pipes and everything seems to be ok... Not replaced the spark plugs yet, but that is on the cards. Only other thing I have done is clean and re-oil the filter.
Check the pipes around and under the airbox, there are small ones to the KLEEN air valve from the carbs.
Also if the bike has been left to stand, the main and idle jets may be gummed up with varnish. Sounds more like the former though.
Weak coil/coils????...worn jets...and double check for air leaks...worth changing plugs if nothing more than to eliminate.