Hey peeps,
Just got in from messing with Gunta - I followed some of your advice and checked the float levels (one was off a little, so I adjusted it back to spec), and checked the jets, which are all unclogged and clean. Fuel pressure is 2.5, and there is but the smallest occasional drop into the carb throat from the #3 orifice at idle, which almost disappeared after dropping the pressure at the regulator. The jetting is stock 40IDF, (115 main, 50 idle, etc) which I would guess is even a little on the lean side for my setup - 2056, Euro H cam, 050 dizz, and dual 40idfs. This thing runs so rich, that your eyes burn after just a few seconds behind it! Revving it makes it look like the smoke machine at an Ozzy concert for cripes sake. You can see the gases make a nice cloud that fills the garage when I pull it out, woohoo.....

Sigh


The ONLY thing I changed was the damn intake manifolds, I replaced a set of stubby shorties, with a set of tall ones. They are about 1.5 inches taller (maybe around there IIRC) and are ported immensely to match the intake ports on the heads. (I have some mild headwork as well, on the exhaust side). Could these intakes be the culprit? Do I need a set that haven't been ported? I'm hoping that's the problem

Any ideas?


Man this stinks

Hey, Jeff
If it was working fine before the intake swap, I would say put the old manifolds back on and try it. If the problem goes away youll know thats the problem.
If you need a hand let me know.
Luke

Well I think you now have more velocity through the carbs. MORE AIR FLOW = MORE GAS delivery.

If it is rich at idle then you may not have the mixture screws right. You should be able to turn each one in till the barrel dies off. If that don't happen then the idle circuit is jammied up (technical term huh?)
Or you said that you are seeing drops form one of the What????? Accel jet nozzles? you linkage isn't right
You shouldn't be able to see gas above the butterfly plates otherwise. Low Idle the gas enters the carb below the butterfly (sorry Throttle plates).
Maybe you just need a lightening bolt spark to lite that mixture. My Mallory 6A with Petronics flamethrower coil Magnacor wires will lite a totally flooded motor.

Give Jake an email, he know's a little about carbs and aircooled engines , and could probably save you a lot of time and aggrevation.

Kevin

I've had 40 IDF with the same jets as you ('cept 120 instead of 115- so even richer) for 20 years.... Always ran rich. I was told that the alternative to rich idle was leaning out at high revs making lotsa heat- not good. Other day I was leafing through my 20 year old Claudes Buggies "weber tech manual" (the BEST guide to setting up webers imo) and came across: "A rich idle can be cleaned up with 2 1/2 to 3 screws out on the air correctors" so loosened the locknuts and cranked 'em all out three turns, pulled out the uni-syn and found everything was still balanced and NO MORE BLACK SMOKE! The CBs book also says this will give better MPGs wich I'll take. Try it. I'll bet yours are at the bottom (cause i've also read "never open the air correctors" somewhere). When the airflow is increased, they will whistle lightly, which is kinda cool too. Good luck!

Thanks guys,
I spent a few hours on it today, I think you're all correct - it hasn't been the same since I swapped intakes, and I can bet the linkage isn't totally right either. Trouble is, I don't have the old ones anymore, I traded them for the current set. I spoke to a dragrace bud, who said that because the intakes have been ported so much (the wall is very thin in spots even) the charge isn't atomizing properly over the length of the manifold, versus if they were narrower like when new.
Whatever the reason, I guess I'll start looking for a new set of intakes to try, ones that haven't been goofed with, and then start fron scratch with the linkage again.
The mixture screws on 1 & 2 work a bit more slowly than the other side - when they're turned all the way in, the motor sputters as it should, however getting them balanced correctly seems a bit tougher to do than 3 & 4 (never used to be this way).

Oh well, I'm gonna place a "want to buy" ad in the classifieds for a set anyways. Anyone have a set they need to unload? If so, shoot me an email

Hey SGB I just read your post as I was proofing my response, THANKS! I'll be trying that next too then - I read as well that they should be shut, when I was rebuilding them. I'll give it a go, probably thursday and let you know what happens, maybe I'll get lucky (insert smiley crossing his fingers)

Hey Luke, what's your ph # again? E-mail me, maybe you can lend a hand getting it tuned properly I'd be thankful

Thank
You
Guys

I swear it'll help- I was amazed I had never seen that particular statement before. The book has like 25 If your carbs do this, try that kinda procedures. I do have the short short realy short manifolds I took off my car recently if'n ya wanna buy 'em, but longer ones give ya more torque at lower rpm.

QUOTE (SGB @ May 24 2005, 05:40 PM)

I swear it'll help- I was amazed I had never seen that particular statement before. The book has like 25 If your carbs do this, try that kinda procedures. I do have the short short realy short manifolds I took off my car recently if'n ya wanna buy 'em, but longer ones give ya more torque at lower rpm.

It's opposite, short manifolds, are for bottom end torque, tall manifolds are for topend high velocity flow.

Hey Scooter, what Venturi's, and what air jets? Something is broken, just swaping manifolds, shouldn't be the problem, unless you had air leaks before, and the leaky air and fuel ratio was right, but now with the new manifolds, you sealed up the air leaks and now runs rich.

No seariously, you broke something, or you changed something, or something is leaking.

Is it just rich at idle, or throughout the rpm range, does it ever clear up? Try going larger on the airs 180.

115 mains seem kinda small?

Gooood morning
I just finished laundry (had to get the exhaust fumes out of my clothes!)

It runs rich through the entire rpm range, even at idle it pushes fog. The venturi's etc are all stock (I forget right now what the numbers are, the sheet is in the garage), and I don't *think* anything is broken, I hope..... But, I won't rule that out. Hey SGB I'll let you know about the shorties, right now I'm tracking down a set of CB talls

Oh well, off to work, where I can't surf...

Whaaa

LATER DOODS

Pull the plugs, see if it's just 1 cylinder that is running rich, a pair, or all 4? You did say 1 side was harder to adjust than the other.

The intakes you said were ported, to match the heads, That shouldn't cause a problem, unless they have been POLISHED. then the fuel will not atomize, it will not mix with the air properly, the fuel just dumps in with out mixing with the air, that would make it seem too rich.

If, they are polished, you can take some 1 inch 80 grit paper, if you have some way to put it on a rod or ? put it in a drill, pull the manifolds, and kina like spiraling down, ruff up the the intakes, you won't take out very much material, you are just trying to ruff up what is there.

If, you can find one of those long drill bits 14" to 16", around 5/16, cut off the drill part, cut a slot in the end, then the sand paper, gets rolled around, you then have a polishing or ruffing tool. You will need a quality steel hack saw blade to cut the drill bit.

QUOTE (V6914 @ May 24 2005, 08:03 PM)

QUOTE (SGB @ May 24 2005, 05:40 PM) I swear it'll help- I was amazed I had never seen that particular statement before.  The book has like 25 If your carbs do this, try that kinda procedures.  I do have the short short realy short manifolds I took off my car recently if'n ya wanna buy 'em, but longer ones give ya more torque at lower rpm. It's opposite, short manifolds, are for bottom end torque, tall manifolds are for topend high velocity flow. Hey Scooter, what Venturi's, and what air jets? Something is broken, just swaping manifolds, shouldn't be the problem, unless you had air leaks before, and the leaky air and fuel ratio was right, but now with the new manifolds, you sealed up the air leaks and now runs rich. No seariously, you broke something, or you changed something, or something is leaking. Is it just rich at idle, or throughout the rpm range, does it ever clear up? Try going larger on the airs 180. 115 mains seem kinda small?

NOT!!!!!!!!!!!!!
how about some of this
hey come here and another thing

Doh, I'll CHeck The plugs next, that was the whole reason I wenttothe tall intakes
(damnthis lousy public keyboard)

How doI measure vacuum?

It's so sunny out right now you wouldn't believe it forRochester.....