Originally Posted by Hesky

AI, I've found my D5R to be really sensitive to low-end needle settings. It seems to really respond to leaning the low-end out ever so slightly more(1/8th turn) giving it much better response but then I would have idle issues much the same as yours. I alway make sure my low-end needle is setup correctly b4 I move onto the hi-end needle but this engine keeps forcing me to tweak the low end. but I got there in a round about way though.
I must admit my nova jp is really easy to tune, maybe its not just because its a 3 port maybe the carb has somethin to do with it. I would try swapping carbs and see where that gets you. the fact you have to screw the hs needle all the way down just to tame the flow of fuel makes me think you have a damaged needle.
As Nightmare suggested try some different plugs also, I fancy tryin some odonnels but there not to common in the uk.
let us know how you get on dude!!