Emulsion tubes? Jetting help!

[Daddybus]

42 DCNF carbs 34mm venturis.
2028 C25 scat cam 7.25:1 CR 40x35.5 heads in a bus. IRS tranny. 60-65 mph at 2500-2800 rpm, 70 mph at 3K rpm.

Currently 60 idle, 140 mains, F24 emulsion, 190 air jet slight flat spot from idle to main circuit transition.

Have tried...
60/140/F24/180 too fat sluggish with poor mileage
60/125/F25/180 too lean gutless no top end

Larger main jet = more fuel, Larger Air correction = more air (leans mixture) What about emulsion tube? What is the difference between an F24 and an F25 emulsion tube?

[Daddybus]

Anybody?

[Hophead]

Idf's run 50-55 idle jets. I do not know if 60's are correct for DCNFs. You still have 130, 135s to play with for mains.

I am just throwing this out there. The Tuner gurus will show up. I vote for too rich of an idle jet.

I had a pair of DCNF's on a 1776cc 25 years ago but I did not need to tweak them as they were set up well. I do not remember any of the particulars.
_________________
70' Beetle Pan off Resto
2110cc
82 X 90.5
P&P 043 40x35.5
9.6-1 comp
FK-8
48 IDA

[Daddybus]

I had 50's and it was too lean. I think that I went to 60's. I'll have to check. My near vision isn't what it used to be. My emulsion tubes are all F25 (what Berg recommends). I installed 140mains/f25/180 air today and advanced the timing to burn all of the fuel. I have ordered 135s and 130 mains. When they arrive I will try the 135s and retard the timing. Heavy buses don't like a lot of advance. I will check the idle jets, they may be 55s.

[DarthWeber]

Have you read this Tech article? It's not DCNF specific but might help you in your tuning: http://www.aircooled.net/gnrlsite/resource/articles/jetting.htm