razzle308
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What jet sizes? 2x 40 dcoe
Sorry to repost but there were no replies. My mechanic friend say im lean. I and the air/fuel gauge say rich. so...... what do you guy's run? pleeeaaaassse?? Hey all. Did mine by the book and runs like a pig.  Worked 2L pinto. (cam - 60 deg ovelap split, 0.47 thou lift, ported, large valves,) Twin 40mm dcoe's 34mm chokes. Main? Air? Emulsifier? Idle? Thanks, Darren.
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fahley
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Re:What jet sizes? 2x 40 dcoe
2012/11/08 17:18:16
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razzle308
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Re:What jet sizes? 2x 40 dcoe
2012/11/08 17:47:06
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Hi Fahley.
Yes i have come accross this.
I kinda guess this is why i ask coz i set mine up according to this but it's not right for my car.
It was running rough on 135 mains. so my assistant said it was lean and put the 155's i have in. then it was spitting out the carbies and rough. I know this usually indicated lean but ive got serious black plugs and soot out the back and the air/fuel gauge said rich.
so i put the 135 back in and changed the idle jets and now it is alot smoother although still rich.
i can still feel it fueling up on cruise.
So i wanted to get a cross section of what others find successful and see where i am?
look forward to do a meet up day and see that one you have - looks nice.
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gazz
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Re:What jet sizes? 2x 40 dcoe
2012/11/08 22:44:08
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155's will be way too rich..
i run large valves and a bigger cam than what you have got and im running on 145 mains and 57 idles. that is on 45's with 38mm chokes.
what kind of air/fuel meter are you using and what kind of webers? are they emissions type? have you played with the mixture screws?
if the plugs are black, the air fuel meter says its rich and its running crap, then sounds to me like its rich......
your right in that spitting through the carb can be associated with lean mixture, but it can also be other things.
i ran my car on 40mm emissions dellortos for a time with 34 chokes, but emmisions carbs are different kettle of fish. i had to run 69 idles and 169 mains to compensate for lean progression circuit.
easiest thing would be to take it to a dyno, that way it can be done properly, but if your just trying to get it to run ok to get it there, then i would be trying something in the ballpark of a 55 idle with maybe a f13 or f2 tube and a 135 or 140 main.
most of my experience is with dellortos im sorry, but if i was in your situation i think thats the sort of jetting i would be starting with.
if you have an email address i can send you some reading that might help you.
good luck
Gazz
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razzle308
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Re:What jet sizes? 2x 40 dcoe
2012/11/08 23:11:32
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Hey gaz. Thanks for your help. I am running an auto platonium air/fuel gauge and a narrow band O2 sensor and it says rich. My friend tends to doubt these things but i think it's telling the truth so I have to tactfully disagree with my friend. as i said the 135's i have seem rich still but it does come down off the end of the gauge if i rev it a bit. I need some jets to play with.
post edited by razzle308 - 2012/11/08 23:14:34
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Wozzah
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Re:What jet sizes? 2x 40 dcoe
2012/11/08 23:44:12
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As Gazz said, depends on the model of the carbs you have.
Best place to tune them is on a dyno, and with someone that does Webers and has parts on hand. Any suggested jetting charts or advise should be A GUIDE ONLY.
A 155 main is awefully big for those carbs on that engine
I would suggest a starting point to be
135-140 main
190 air
F16 or F2 Emulsion (probably an F16)
40 pump jet with 0 bleeds
45F9 idle jets
Check the size of your needle and seats too, should be 1.5-1.75.
Cheers
Woz
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razzle308
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Re:What jet sizes? 2x 40 dcoe
2012/11/09 14:28:12
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Just to keep everyone in the loop: Hi Gazz. Thanks for that info. I have played with that DOS prog before. My dcoe's are non emissions - i believe they came off an alfa. I have been away from the for a long time so I am having to refresh everything. While i have rebuilt motors before I have never taken one from modded rebuild to tuned and so am finding I am having to deal with many different issues at one time. I used to play with the weber alot before but the motor was standard so i knew how it behaved and could more acutely address subtle changes I have the Pat Braden weber book. I have read it before but I got it out and started to read through the jetting side again. Just like you said to see where the mains and air correction come into play. The air/fuel gauge is new and i guess never using one before I don't know how well to trust it. Thats why i wanted the feedback to see where everyone sits. If i am with coo-ee and the gauge indicates this then i know it is dong what it should and then i can tune according to it. I think with your info and some other comments - i can trust it. That with other indicators I am very confident now i am rich. I got all my jets out last night and i have a couple to play with. unfortunately i got nothing really in idle jets so i will have to chase some up. Even the weber place here in my area said he hasn't worked with them for years. :-( Be alot easier if it wasn't spewing oil out the back  .
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RS 2000
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Re:What jet sizes? 2x 40 dcoe
2012/11/09 14:51:28
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razzle308
Hey gaz. Thanks for your help.
I am running an auto platonium air/fuel gauge and a narrow band O2 sensor and it says rich.
My friend tends to doubt these things but i think it's telling the truth so I have to tactfully disagree with my friend.
as i said the 135's i have seem rich still but it does come down off the end of the gauge if i rev it a bit.
I need some jets to play with.
Narrow band o2 is useless they are designed for lambda/stoich/14.7AFR(closed loop systems) anything richer than that will read rich and anything leaner will read lean on your gauge. Unless it is wideband it will just confuse you. on the good old carby engine your narrowband gauge should always read rich unless engine is decelerating. Cheers
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the_cheese
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Re:What jet sizes? 2x 40 dcoe
2012/11/09 16:55:14
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Try Jim at Perth Carburretor Specialists in Ossie Park, 131 howe st - 9444 4618. I had his mobile number but have since lost it. He should have plenty of jets on the shelves!
Cheers
Nick
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ratta tat tat
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Re:What jet sizes? 2x 40 dcoe
2012/11/09 20:00:00
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Haynes weber manual has specs for 2 x 42DCOE on 2000 Pinto.
32 chokes
4.5 Aux venturi
125 mains
f16 emulsions
180 air correctors
0.50F9 idle
0.40 pump jet
0.50 pump valve
2.00 needle valve
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razzle308
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Re:What jet sizes? 2x 40 dcoe
2012/11/09 20:21:28
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I have a 60thou over bore and a modded engine so when i determined that the carbies had 30mm chokes I went up to 34mm chokes.
A decision I may have to regret soon - we'll see...
34mm chokes = 135 mains and i think the 200 a/c were due to nearest available.
so thats why i have what i have.
I'll look into the wideband sensor - from here at work today I can't determne if i can use a wide band with the gauge or not.
Thanks ratta.
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jimmyd
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Re:What jet sizes? 2x 40 dcoe
2012/11/09 22:15:22
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While not exactly the same as DOCEs, I'm running early italian 40 IDFs with 34 chokes, 4.5 aux, 135 mains, 180 airs, 57 idles, F7 emulsions, 50 bleeds on .040" o/size with 'Vizard stage 1' ported head, back cut valves, 10.5:1 compression, mild crow 26874 billet cam, large bore pacemaker headers and 2 1/4 single box exhaust. Using F7 emulsions for the fatter off cruise progression, on the dyno fuel runs in the 13s across the range - technically slightly rich and while no rocket ship theres no spitting and pulls clean. http://www.youtube.com/embed/w0E7-Wl4uU4
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razzle308
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Re:What jet sizes? 2x 40 dcoe
2012/11/10 00:54:13
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Woah thats so like mine.
I did the porting myself but i followed vizards instructions. similar valves. similar compression, same extractors.
awesome - thanks
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razzle308
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Re:What jet sizes? 2x 40 dcoe
2012/11/10 00:57:02
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man i sounded 16 then! 
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Wozzah
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Re:What jet sizes? 2x 40 dcoe
2012/11/10 08:11:48
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razzle308
I have a 60thou over bore and a modded engine so when i determined that the carbies had 30mm chokes I went up to 34mm chokes.
A decision I may have to regret soon - we'll see...
34mm chokes = 135 mains and i think the 200 a/c were due to nearest available.
so thats why i have what i have.
I'll look into the wideband sensor - from here at work today I can't determne if i can use a wide band with the gauge or not.
Thanks ratta.
No need to stress, 34 chokes will be fine once you get the rest of the jetting sorted Woz
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