Idle jet sizing
 

Hi,
I've read a few threads on modification that were done to the carbs and was wondering if someone can help.
On the Zenith 40 tin carbs I took the advice to remove the enrichment circuit therefore everything is plugged with no leaks but this naturally causes a lean mixture throughout the whole throttle range. The Idle jets are 47.5 and have no choice to increase the size because of the missing fuel that came from the enrichment circuit.
The enrichment jet are 50 therefore calculating the surface area of both idle and enrichment jet I get a value "A".

Example:
Idle jet 47.5 = 0.7085 mm sq
Enrich jet 50 = 0.7850 mm sq
Total = 1.4935 mm sq

Could I assume that I can calculate the surface area of the new idle jet to equal that "A" value?
60 = 1.1304 mm sq
65 = 1.3260 mm sq
70 = 1.5386 mm sq

At 50$ a set of 6 I would like to avoid spending too much for trying out which one works.http://forums.pelicanparts.com/suppo...ool_shades.gif

take a 0.55 jet drill to the 47.5 idle jets. good starting point.

Thanks John,
I remember a while back I used "Butterfield" bits that were of good quality.
Would you have any recommendations?

The enrichment circuit is off during acceleration and constant throttle applications so there is no contribution to fuel mixture when working.

52 to 55 idle jets are good to go with per John Walker's recommendations.

I keep on forgetting this!

Thanks