Must be the week of the carb. After 3 days of soaking in Kroil, a trip to the oven, ice inside the vent, application of slide hammer, I was able to pull my 38mm vents.

My replacement vents have nop markings, and do not have the relief for the secondary vent. So which end is up?

Thanks,

Carlos

you didn't show the other end, but that looks like 'up' to me. tapered (radiussed, actually...) end faces the airstream...

There should be a small depression for the set screw which will only line up one way in the bore. Fat end up.

Thanks Rich and Chris.

I installed them so the pic in my first post is looking down the throat. The biggest ID is on that end and it tapers to a narrower ID.

This must not be an OEM vent. Got it from CB. Looks like it was milled from a piece of Al. No numbers on the vent, no relief for the secondary vent or the set screw. The difference between the OD and ID of the 38mm vent is so tiny that I couldn't infer the proper orientation. It may still be wrong. If it doesn't rain tomorrow, I'll sync them up and see if I can put the hammer down.

Carlos

I bought some 32s for my 40 IDFS from CB. No markings
but they did have the indentions for the set screws.
On mine the biggest inner diameter is at the bottom of the venturi.
The top has a more rounded edge and the narrowest part of the
venturi is closer to the top than to the bottom.
In the picture the venturies are "upside down" from how you
would install them in the carb and the CB 32 vent is on the left
and the factory 28 vent is on the right.

--- bill

I thought you were installing them in 44s Carlos.
38 vents are pretty much useless in 40s without significant mods to the upper section of the carb and to the secondary vents. If the primary vent isn't the most restrictive part of the throat you won't get enough depression at the right point to properly suck fuel.
Not only that the bottom end torque will suffer big-time with such a large opening.
I'm using 36s in my race carbs right now, and I still had to rework the top end for flow.
What cam is in your engine, & what displacement?
Here is a pic with a modified secondary venturi on the left.

Hi,
Well getting ready to give it a shot to go out an wake up the neighbors.
[QUOTE]What cam is in your engine, & what displacement?
Chris, I'm at 2270, 163/86b, using Dell 45's. Decided to go to smaller vents because I've been trying to get rid of a lean condition at transition to mains. I was already up to much bigger mains and idles (70, 165) than anyone else that I know of running a similar combo (must are running 44 webers).

Dell secondaries are similar to your modified weber. I'm sure that they are no as functional as your modified one, but fall somewhere in between it and a stock weber secondary.

I'm hoping that Kit Carlson can get his FI system up for production before next spring. Otherwise, I'm planning to go Megasquirt and haunting Dave. I think I've already spent the initial buy in cost for MS in jets.

Congratulations on the win! Checked the regional standings, if you had a full season, that could have been you at the top.

Carlos

All,

Boards are being built. I need to bring a few more things together. Hope to be ready before the end of month.

Kit