there a chance that the initial throttle plate position is incorrect? as in too much or too little of the transfer slot covered/uncovered?
what i'm trying to say is, if you take off the carb, do you have it sqared up front and back?

 

No. If I show a "square" of the transfer slot front and back, my idle rpm would be too high...probably 1500rpm. Basically right now, there is just a tick, if any, of the transfer slot uncovered front and back.

 

Only about .020 of the transfer slot should be uncovered before you set your idle speed. If it's suddenly going rich during tip in, then it may need a slightly smaller IFR. Is your idle fuel correct? Can you go any leaner on the idle mix?

You can also try increasing the idle position to get the right amount of transfer slot(if it's wrong) and then adjust the idle timing to compensate. Could it be too much idle timing and not enough throttle?

But I imagine if not enough transfer slot were uncovered, it would go lean and not rich during tip in. The less that's uncovered, the less area there is for intake vacuum to draw on the circuit, so when you tip in and start to uncover it, it would take a second for the transfer slot to start flowing fuel, so it would lean out.

 

i would have thought as well that if too little would actually cause a stumble (lean) on tipping it, but 0.020 in a demon is exaclty square (at least in the demon manual)
i thought that was crucial to have them open like that.
does your carb have any other idlespeed adjustment (apart from the throttle plate settings)?

 

No. That is one feature I like about the Demons, that idle air valve.

 

After installing my new port matched and flow tested Air Gap from Dr J, I decided to open the dialogue back up with Patrick at Pro Systems to try and fix my cruise AFR issue (everything else if working great). The tweaked Air Gap balanced my AFR between the left and right bank nicely...a problem that had me scratching my head for a year. I can also feel some more power and my over all WOT AFR went up, so I will need to add some jetting to make use of the increased efficient and balanced air flow. My intake can now flow as much air as my heads can pull, which is always good and I still have the functionality of a dual plane intake which is nice around town.

After sending Patrick an email yesterday to open my issue, he told me to try drilling my top emulsion ports out to .032. He then said "E Back Effect." Any idea what that is?

 

Not sure on his comment. Not familiar with that phrase. And make sure you get a GOOD set of machining drill bits for drilling that stuff out.

 

never heard of it. maybe it's differenmt when written, no idea. i'd be too scared to drill. you can easily **** up a perfectly good metering block doing that.
those carbs (pro systems), do they have no changeable emulsion bleeds?

 

No. The metering block they put in mine is the 11180 block and is not tapped for changeable emulsion ports. I have a set of Barry Grant drill bit index bits...now I just need to find out what drill bit index number corresponds to .032. For my information, 67mustang302, what /where can I find good machining drill bits. I already have a few bid drives to use with these small bits (hand drilling).

 

picture is from "130050 - Barry Grant Drill Sets" at jegs, maybe that helps? 67?