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Mon Apr 07, 2008 1:56 pm

Sorry to start a new topic if I am. Simply put what is the stock jets in a 34 pict 3 carb? I purchased one from MOFOCO and installed it. Runs good. Its a Bug motor I have in a BUS. Reason I ask here is bus guys say 125 main, 60 air corrector & 57.5 pilot jet is the correct jetting (according to the Bentley Manual) in a BUS carb. Basically a little more rich going down the road than a bug. Is this a myth? Please someone clarify if they can cause I thought all 34 carbs are created equal.

Mon Apr 07, 2008 2:31 pm

Well you need to go here and read up. It will be helpful to know the "flange number" on the carb and also the number on the distributor you are running.....

http://www.thesamba.com/vw/forum/viewtopic.php?t=156127

Mon Apr 07, 2008 5:10 pm

I just tried to look at the carb and all I could come up with is 113 129 031K written on a tag on the carb. I'll have to unbolt the carb to look at the number because I do not see it. This is the carb I have which I emailed Randy to see what jetting is in there: http://store.mofoco.com/VW_34_PICT_3_CARBURETOR_1600_ENGINE_p/vwp-113-129-031k.htm

I'm using Aircooled.net's Distributor tuned to the 34 pict-3:
http://www.aircooled.net/new-bin/viewproductdetail.php?keyword2=IGD0001&cartid=0403200816171741

Here's my setup

Mon Apr 07, 2008 7:08 pm

Sounds a little lean to me.

Quote: 1971-1974 34PICT/3 Carburetor

Venturi: 26mm
Power (Auxiliary) Fuel Jet: 60
Main Jet: X127.5
Float Needle Valve Diameter: 1.5mm
Air Correction Jet: 75Z (80Z for Ghia)
Float Weight: 8.5 grams
Pilot (Idle) Jet: 55
Accelerator Pump Feed: 1.3 - 1.6cc/stroke
Pilot Jet Air Bleed: 147.5
Fuel Pump Delivery Pressure (max): 3 - 5 psi
Accelerator Pump Jet: 50
Delivery Capacity (min): 400cc/min @ 4000 rpm

The jets in Dave's 34 PICT/3 carburetor are -

* Main jet - X130
* Idle jet - 55
* Air correction jet - 80Z

I have always heard that the minimum recommended main jet is 127.5. That's considered by some to be borderline and can cause the engine to run just a smidgen warm due to less evaporative cooling.

It makes for some pretty decent gas mileage, so that's what I have been running. But I do have to watch my temperature in the summer months.

I think you'd probably want to contact MOFOCO to see what kind of jets they're sending their carbs out with and then go from there. But I think a minimum of 130 would probably be better for your situation.

Mon Apr 07, 2008 7:53 pm

I sent MOFOCO an email. If I don't hear from him by lunch time I'll just give a jingle over there. So I wonder why wouldn't VW just leave the 34 style carb with standard jets across the board. I mean I can somewhat understand them changing a dist and matching it...but when it comes to a BUG motor or a BUS motor...Whats the difference...they should be the same jetting for either.

Previous to the 34 I had a 30/31 with adapter on the 1600DP and that was running very lean, because it would stumble alot if not warmed up for 5-10 mins in 30 degree weather.

Tue Apr 08, 2008 12:57 am

Ataristyle wrote: but when it comes to a BUG motor or a BUS motor...Whats the difference...they should be the same jetting for either.
I was looking at MOFOCO's advertisement for a 34 Pict 3 carburetor, and it doesn't say what brand it is.

I doubt seriously that it's an original Solex, so your carb could be made by either Pierburg, Brosol, Bocar, or some other company we have never even heard of.

This is not outside the realm of possibilities, since, IIRC, MOFOCO manufacturers their own head castings.

Now before somebody from MOFOCO pops in here and protests, I am not suggesting that there's anything wrong with MOFOCO's 34 Pict 3. I have no knowledge of, or experience with, their 34 Pict 3.

And that is exactly why I am suggesting that you contact them and get more information.

To borrow from that old phrase: assuming that all 34 Pict 3's, from all the various companies making them, are going to be made to some sort of exacting standard ... makes an "ass" of "u" and "me".

Oh yeah, here is a spec chart for original VW Solex carbs, so you can see that even with the originals, there was some variation.

Tue Apr 08, 2008 8:42 am

Talked to MOFOCO and the Main jet is 130, Pilot Jet 60 & Air is 75. The bigger the Air corrector the more air is introduced into the carb then, correct?

Tue Apr 08, 2008 10:40 am

Ataristyle wrote: Talked to MOFOCO and the Main jet is 130, Pilot Jet 60 & Air is 75. The bigger the Air corrector the more air is introduced into the carb then, correct?
Something like that. The way I understand it, there's kindof a juggling thing going on between the main jet and the air correction jet.

And 130 on the main jet sounds like a pretty good starting point. You could run that for a few days and then check your tailpipes to see how sooty they are and your sparkplugs to see how black they get and work from there.

Tue Apr 08, 2008 11:35 am

Bus, Thing, and Ghia were jetted different, due to the style of air cleaner for one thing. Also, buses need to have larger jets due to the faact that the engine is working harder.
And BTW, that intake manifold on your bus is for a Type one, not a Type 2. Type 2 intake manifolds were taller on dual ports. Note how the hose from the air cleaner is going down hill to the carb.
I can look in the factory shop manual ans it should show what jets are needed for a 1600cc DP Type II.

Tue Apr 08, 2008 12:32 pm

Russ Wolfe wrote: Bus, Thing, and Ghia were jetted different, due to the style of air cleaner for one thing. Also, buses need to have larger jets due to the faact that the engine is working harder.
And BTW, that intake manifold on your bus is for a Type one, not a Type 2. Type 2 intake manifolds were taller on dual ports. Note how the hose from the air cleaner is going down hill to the carb.
I can look in the factory shop manual ans it should show what jets are needed for a 1600cc DP Type II.

I knew I had it.

Wed Apr 09, 2008 12:17 am

It took me awhile to wrap my mind around it, but now it makes sense to me about the different air cleaner requiring different jets.

I think that the longer, more convoluted air cleaner setup creates a slightly stronger vacuum above the throttle plate. And that slightly stronger vacuum calls for a slightly smaller main jet to keep the fuel/air mix correct.

But yeah, I think you should shoot for Russ's Type II specs, since those are VW-approved and factor in the Type II's air filter.

Wed Apr 09, 2008 4:53 am

Ok, thank you much. Makes sense what you say. I'll try dialing in what I have, but more than likely will order the correct jetting setup. Thanks everyone for your help!

Thu Sep 26, 2013 7:31 am

I'm running a new 1641 with Engle 110 cam, 009 with Ignitor, and German Solex 34 pict 3. I swapped the 127 main jet for a 135 and it helped tremendously. Still doesn't idle real well when cold, but is super happy when warm. Choke seems to be working, but I'm going to replace anyways. Prior to swapping the jets, she was misfiring up through the carb consistently during acceleration. After swapping jets, she did it one time on my way home... but overall, she ran much better.

Just looking for opinions from you guys as to what combo to run in my 67 double cab with a bug AE case 1641. We live in Florida, so it's hot and humid here most of the year... Bosch coil, stock heads, NGK plugs at .028", valves at .006", and full advance at 28-30 degrees. Stock German bug exhaust, and cone shaped air filter on beetle cleaner manifold.

Thu Sep 26, 2013 9:55 am

Don't forget manifold preheat....You can jet all day, but if you're not atomizing fuel properly you're going to be running rich as heck despite it feeling "good"

Ben