rough idle

[eddyserow]

Hi all, can anyone confirm/pinpoint cause of a rough idle on my 91 NC?
Carbs have been stripped and are running 118/120 jets, valve clearances are fine too.
Bike runs ok through rev range, but has rough idle and occasionally when i rev engine and revs drop to idle she sometimes cuts out?? Carb rubbers look original with some tiny splits to outer edge but i have sealed these with engine silicone gasket.
Any help would be greatly appreciated.
Tom

[magg]

Lean idle mixture setting could be a place to start.

[skinnydog0_0]

check the a/f screw settings as magg says above.
Also check the pilot jets are not blocked
An air leak tends to make the revs hang rather than run rough.
EDIT: also check the carb balancing

[eddyserow]

Hi, I'm finding it very difficult to balance the carbs everything else on carbs has been checked and is fine.
When balancing i find 2 cylinders high and 2 low and it's very difficult to match without the engine going very rough???
Any other help would be great as I'm lost as to the rough idle.
Thanks

[jedidude04]

You're supposed to match 2 cylinders to eachother (i think its 1 to 3 and 2 to 4), then you need to balance both to each other, if that makes sense. When your doing this your idle will change and you will need to change the idle either by lowering it or raising it.

Although i don't know if there's any difference concerning this between the nc30 and nc35..