Weber carb question Options

[KaptKaos]

I have 44 idfs. The venturis are 32s. I have read that the 32 is the smallest for the 44s. Is that the case? I thought I saw 28s, but I am not sure.

Does anyone know for certain?

If it's possible, does anyone have 28 vents for 44idfs?

Please let me know.

Thanks!

[Aaron Cox]

make some on a lathe? (IMG:style_emoticons/default/tongue.gif)

tried john at aircooled.net?
CB performance?

IIRC 28 is only available in a 40 OD

[Twystd1]

I have seen aftermarket 28s and 30s for the 44 IDF. (Custom)

And YES to your question. The smallest venturi that weber made for the IDF is a 32. (To my knowledge) Thats the smallest you can buy from the weber parts guys anyway.

Gimme us list of your existing jets and E tubes again. I forgot what ya had.

Clayton

[Aaron Cox]

I have seen aftermarket 28s and 30s for the 44 IDF. (Custom)

And YES to your question. The smallest venturi that weber made for the IDF is a 32. (To my knowledge) Thats the smallest you can buy from the weber parts guys anyway.

Gimme us list of your existing jets and E tubes again. I forgot what ya had.

Clayton

for a 44 IDF that is.....

[KaptKaos]

I have seen aftermarket 28s and 30s for the 44 IDF. (Custom)

And YES to your question. The smallest venturi that weber made for the IDF is a 32. (To my knowledge) Thats the smallest you can buy from the weber parts guys anyway.

Gimme us list of your existing jets and E tubes again. I forgot what ya had.

Clayton

emulsion tubes F11
Air Correction 190
Mains 145
Venturis 32
idles 0.5

[Aaron Cox]

LOL on the mains.....

i have some 135's or 130's you can try before you order some.

[Twystd1]

Thanks Aaron. Dats what I meant........ 32s for 44s.

AA is right about your jetting. You SHOULD borrow AAs jets. They are closer to what you need.
And go down on your airs. 170 -180s maybe.
Maybe try 40s or 45s for your idles.

Stay with your F11 tubes.

Whadya think Aaron?? That sounds like a good starting point to me.

Clayton

[euro911]

I have some .45 idles we can try out Joe ...

[Aaron Cox]

wouldnt you step up a size on the air correctors clayton?

[KaptKaos]

So I went out and checked a few things.

First, I checked the timing. It's an 050 and its about 5 degrees at idle and about 28 degrees at 3500 rpm. It seems to be advancing properly, so that's good. I haven't dropped in the Mallory yet, as it is a "loaner" and I don't want to blow it up.

I also checked the compression. All 4 are between 110 and 120. It's an old gauge that I haven't used in years, so I am not sure that it reads correctly, but they are all consistent.

After doing this, I took it for a quick spin around the block. It just won't pull above 4000. I am worried that those 32 vents are just too big. I figured it would clear up at some point, but it really doesn't. I plan to try new mains and ACs, but I am starting to worry that the carbs might need to be smaller. (IMG:style_emoticons/default/sad.gif)

[Twystd1]

You can tweak that 050 dizzy to be at 12 - 15 degrees initial. That will help the bottom end immensely.

Why it won't rev past 4K is another story.

Could be ignition, could be carbs, could be valve springs, could be shit gas or a compendium of any of the above.

Which one ya wanna start with?

C

[Aaron Cox]

the carbs should atomize BETTER with more velocity (higher engine speed)

too retarded of timing? but you checked that.

im gonna guess ignition....
does it start lurching at 4grand? (rev limiter rotor? lol)

valves adjusted right? compression check says yes.... one is not open.

think small cc race motors that pull 7-8000 rpm. They can use the big carbs to make the power high up.... i would think your situation would get better with more rpm.

hmmmm......


i am gonna guess it is ignition related.

[euro911]

Double check your dwell angle first. If its not right, everything else will be out of whack.

Do you wanna make your dizzy timing adjustable from the driver's seat? (IMG:style_emoticons/default/biggrin.gif)

[Twystd1]

Aaron to answer your air correction jet question.

Bigger airs mean you will bring in the main jets FASTER. (earlier)

I know thats counter intuitive. Yet thats the way they work.
It's less a fat or lean thing. It's more of a transition timing event.

This is one of the things you can do if you get a flat spot in the transition from idles to mains. Try a bigger air corrector jet.



FOR JOE,
I think you may have an ignition problem of some sorts. (Like AA said)
You could Index that Mallory correctly and throw it in. And see what happens.

OR:

Ya might want to swap your coil and rotor/cap and see if that makes any difference.


If it is carb related. And based on what you stated above.
The next approach might be to do the following:

If you are running out of steam at 4K. Try a bigger main jet.

NOTE: A bigger main jet doesn't really affect the lower RPMs. It will affect transition a bit after most of the idle circuitry cuts off an you are running on the Mains only. So a bigger main won't make any difference down low.
If a bigger main helps the problem. just keep going up in main size.

NOTE: If ANY of your air bypass screws are open. CLOSE EM. And start a fresh tuning session..


Clayton


C

[Aaron Cox]

Double check your dwell angle first. If its not right, everything else will be out of whack.

Do you wanna make your dizzy timing adjustable from the driver's seat? (IMG:style_emoticons/default/biggrin.gif)

pertronix dont have dwell angle issues..... LOL

[Aaron Cox]

clayton... he has a 145 main. HUGE for a 1.9

could he be getting SOO much fuel that it just wont burn it all?


Joe - what are your accel pump squirters set at?

[Joe Ricard]

Aaron quit hinting around the bush.

YES HIS MAIN JETS ARE TOO BIG. You will not make more power till you step down the main jet size to 130 with a 180 to 200 Air correction.

I bet you were poofing fire balls out the tail pipe when let off.

the 44's are probably too big to make the most out of the engine but it will run and the faster he goes the better it will run.

Lean it out and watch it bounce off the rev limiter.

[euro911]

pertronix dont have dwell angle issues..... LOL

He's running a '050' with points right now ...

... YES HIS MAIN JETS ARE TOO BIG. You will not make more power till you step down the main jet size to 130 with a 180 to 200 Air correction.

I bet you were poofing fire balls out the tail pipe when let off ...

You can see and smell raw fuel coming out of his tailpipe. Light a match to it and you'll have a flame-thrower (IMG:style_emoticons/default/blowtorch.gif)

At high revs, balls of mist float up out each of the velocity stacks too (IMG:style_emoticons/default/sad.gif)

[KaptKaos]

I just lobbed John @ Aircooled.net an email asking for his advice and part numbers. I will let you all know what he comes back with.

Mark, might want to try those .45 idles. I may come to class tomorrow. Might drag Dad along too (IMG:style_emoticons/default/smile.gif) We'll see.

[KaptKaos]

Update.

John from Aircooled.net wrote me back and said:

I recommend

32
F11
55
125
200

your current mains are HUGE

I guess he was talking to Aaron (IMG:style_emoticons/default/poke.gif)

So I will order the idles, the mains and ACs now. He's got a great policy, so I can try these out and see how they go.

Any input or should I just place the order? Please let me know.

Thanks!