hey all, was just wondering if screwing in the emulsion tubes/need jet holders would have the effect of leaning out the upper rev range slightly? What about screwing in the main jet inside the tube? Cheers

The emulsion tubes and main jets aren't adjustable - they're either tight or loose. If you want to lean out the upper rev range, your best bet is swapping to slightly smaller main jets. You could lean out the pilot screws, but that will affect the whole rev range (particularly lower).

The mixture is actually far too rich and fouling plugs, especially in mid rev range. Someone put in 40's replacing the 35's, so i think smaller pilot jets are in order?

Take the shim washer out of the carb needle (this will lower the needle and lean out the mid-range)

It's odd that its running 40 pilots..

What air-intake / exhaust setup do you have?

Id dont think there are shim washers in place, unless thats how they come standard? The system was welded by myself with bends similar to the original, sort of.. but the fuelling's still close to what it was before, ie. way too rich & fouling plugs if revd in midrange for a while. Il take the carbs off (again!, and again...) and look whats above the needles. Otherwise il try standard jets.

Are NC30 jets unique, or can other honda jets fit?

#40 pilot jets will foul plugs easily. Change them to 35's, you can get them from any good dyno place or mechanic.

35's are proving a little expensive, will they really make such a difference? ie. fouling vs not fouling?

MexicanGringo wrote:35's are proving a little expensive, will they really make such a difference? ie. fouling vs not fouling?

Yes!!

I can send you 4 x used 35's in good nick for five pounds. PM me if interested.