Hi all just got some 40IDF carbies and Im stating to pull apart clean up a bit before they go on the car. Before I order casket kit etc for them Id just like to know what other dubers would jet these for a 1640 w/-engle 110 cam and mildle ported heads runing at 9.5 to 1 comp.
I also have thunderbird extractors as well if that make any diference and heads have std size valves.
I have a weber book to help as well just interested in first hand knowledge.
Cheers Nige:thumb

Try emailing places like CB Performance and AirCooled.net in the states for advice.

From memory we talked to CB when we were looking at running the IDF's on my bug.

Go to the library are try and get Weber tuning manual

Also get you self a synchrometer

The first part is selecting your vents. A 1640 should atleast be 32's.
28 are too small. If you check AC.net there 1600s update they sell changes the 1600 pre-jetted IDF kit with 32 vents.

Mains should then be 4.1'ish times the vent, so 4.1 x 32 = 131.
So I would go with a 130.

Airs are usually mains + say 50, so something like a 180 or 200

Idles are dependent on motor and aint really a measure of anything. MOST IDF's go with 50's but i was running 40s and 45's in mine as that was what set the mixtures at 1 1/2 turns out.
In hind sight i should probablly have gone with 50's and just set the mixtures almost closed - the smaller idles blocked easily.

This is/was for say a stocked valved head. Could/would be different if you were running 50mm inlets

Thank guys thats great.
I have the weber tuning manual just wanted to hear from people with experiance for a bit of confidence in what I thought.
I am preparing an order to CB's at the moment with all the stuff I need.
Want to get jets & kit sorted first.

Cheers Nige