Weber jetting versus Dellortos

[bugnut68]

Since my 45 Dells turned out to be boat anchors, I've since hunted down a set of 44 IDF Webers that are currently en route to my hot little hands.  Just curious as to how the jetting should be for these as compared to the Dells, identical or slightly different?
Engine combo: 2017cc, 42x37.5 valves, 8.6:1 compression, 1-5/8 exhaust with 2.5 inch muffler, Engle 125 cam with CB Performance 1.25 rockers... currently at 4,800 feet elevation.

My dells were jetted with 180 airs, 150 mains and 55 idles, I believe.  Just wondering if the Webers will be the sam

[bugnut68]

I'll assume by the silence that the jetting should be the same...?

[Bryan67]

Should be the same. But you might have to up a little on the idles and mains.

[Bruce]

Jets for Webers are in no way related to the sizes for Dellortos. 

When you are picking your Weber jets, throw away all notes on Dellorto jet sizes.

[bugnut68]

Any recommendations?  Perhaps I oughta invest in the Weber tech book... the Dellorto manual Hotrodvw loaned me was helpful, even though my carbs are no longer useful/of value...don't worry, Eric, you'll get it back!  I'll either mail it to you or else bring it with me when I come to Eugene in early July.

[Jim Ratto]

every time somebody wants jetting advice they NEVER say what they have for venturies, and without that key piece of evidence there's NO way to tell anybody a thing.

[bugnut68]

The vents are 38's, the rest of the jetting: I only know I have a set of 65's for idles in there, and a set of 55's came with them as extras.  I believe the airs are 200s and mains if I recall correctly are 165s?

[TexasTom]

Considering the 38s, the jets you have are just about right (200A, 165M)... you might have better luck with some 60 idles and possibly 160 mains, but certainly worth giving it a try.
In my opinion, you'd actually be better off with some 36 vents ... won't be quite so soggy down low, but you'd have to change the jetting for sure then.
Just my $1/50 ...
TxT

[bugnut68]

Thanks, Tom, I'll see where I'm at once I bolt them on... can always make some changes to optimize things later...

[Bruce]

.... they NEVER say what they have for venturies, ......

Same goes for the E-tubes.  Without that, main and air jet recommendations are worthless.

Ryan, remember how I told you to throw away the 70 Dellorto idle jets?  You can do the same thing with the Weber 65 idles.

[bugnut68]

.... they NEVER say what they have for venturies, ......

Same goes for the E-tubes.  Without that, main and air jet recommendations are worthless.

Ryan, remember how I told you to throw away the 70 Dellorto idle jets?  You can do the same thing with the Weber 65 idles.

forgot to mention F11 emulsion tubes...Appreciate the advice, Bruce... what are your thoughts on the 55 idles?  Too rich for my elevation or at least close enough to start with?

[Bruce]

The 55s will be a good start.  Probably a little rich, but good to get it running.

[bugnut68]

Okay, I stand corrected on my jetting.  My eyes deceived me.  I indeed have 55 idles in there and 200 airs, but the vents are 36's and the mains are 140s.  I'm positive of this now, I didn't look close enough the first time, but that's what I've got.  My thought is 140s are going to me way too lean for where I'm at (4,800 feet).

[TexasTom]

In that case ... 55 idles should be good, try 150 mains to start. You may be able to lean them down to 145s considering your altitude.
If you have the proper guages, measuring to verify jet sizes is always a good idea
Hope it runs great!
TxT

[Bruce]

  My thought is 140s are going to me way too lean for where I'm at (4,800 feet).

I wouldn't make that conclusion.  My bet is they will be pretty good.  Enough to get you started.  Then see if they are rich or lean.  Spend money on jets only when you know this.

[javabug]

my carbs are no longer useful/of value

I'll pay for shipping if they're no longer valuable! 

[bugnut68]

I hear ya, Bruce, my guesses are often inaccurate as I'm at that steep part of the learning curve with an engine such as this...  I'm hoping to have these carbs on the engine this weekend and running, and will see where things are at once I have a chance to get it in the car and going down the road.  I had second thoughts about my comments regarding potentially too lean as I realized the elevation of the guy I bought them from has to be considerably lower than me (he's in the Fresno, Calif. area). 

On my lunch hour I took a trip out to my buddy's shop yesterday... had time to pull one carb top off and look inside, looked VERY clean and the float setting was right on.  Hopefully the other side is equally impressive.

[Bruce]

... I realized the elevation of the guy I bought them from has to be considerably lower than me (he's in the Fresno, Calif. area). 

Always assume the PO knew nothing.  Don't base anything from the PO's experience.