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nybugguy Samba Member
Joined: September 21, 2008 Posts: 117 Location: Upstate New York
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Posted: Fri Jul 23, 2010 3:21 pm Post subject: dual weber jetting.........help |
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Can anyone tell me what would be the standard main jetting for 40idf dual weber carbs. I just purchased a 1835 and they have 115 main jets and 50 idle jets. It seems to be loading up a bit and holding back when stepping into the throttle while driving. These carbs are all new to me so any help would be appreciated.Also, is there any place I could buy a jet kit with various sizes so that I could get them right? Any other suggestions?Thanks |
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nybugguy Samba Member
Joined: September 21, 2008 Posts: 117 Location: Upstate New York
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Posted: Fri Jul 23, 2010 4:49 pm Post subject: |
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Can you get jetting from Mid America,bugstuff,jc appletree or any of those kind of places or is there a specific place? |
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sturgeongeneral Samba Member
Joined: June 23, 2005 Posts: 2460 Location: Sacramento, California
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Posted: Fri Jul 23, 2010 4:56 pm Post subject: |
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Jets are expensive, keep in mind. I would first pull the carbs, clean them, and blow through each jet and port. Even out of the box a good cleaning is necessary. You may be surprised. _________________ Street legal fiberglass rocket ship
2005 Lotus Elise supercharged
1974 Chevy Corvette
My fiberglass car collection!
In honor of bowtie56jw:Another victim of the nasty "C" Praying for ya Jeff!
My exwife said if I towed home one more bug she would leave me. You know, every once in a while I miss her |
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nybugguy Samba Member
Joined: September 21, 2008 Posts: 117 Location: Upstate New York
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Posted: Fri Jul 23, 2010 6:31 pm Post subject: |
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I thought they were like 4.25 a piece.Is that expensive? Where do you buy yours? The most important question is what is your main jet at.Mine is 115 |
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Letterman7 Samba Member
Joined: March 14, 2004 Posts: 3198 Location: Downingtown, PA
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Posted: Fri Jul 23, 2010 7:09 pm Post subject: |
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I usually buy my jets from Pierce Manifolds. They have a pretty good tech department and some good on-line articles. 115's are actually pretty small for 40's. There must have been a reason for it - like the carbs were on a smaller motor. My best guesstimate without knowing anything internal to your motor would be to step them to 130 or 135. I'd get a range starting at 130 to 140 if you could afford it and start in the middle and tune from there. And, do as the general says, a good cleaning can go a long way. Make sure your internal fuel filters aren't plugged and you're getting a good fuel flow at speed. |
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nybugguy Samba Member
Joined: September 21, 2008 Posts: 117 Location: Upstate New York
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Posted: Fri Jul 23, 2010 7:43 pm Post subject: |
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I will try a good cleaning first.Is pierce manifolds web site the same as the name?Also,what are you running and what are your idle and main jet settings? my idle is 50 and the main is 115 on my idf40 dual webers. I am new to these so can you direct me to the internal fuel filter or a website that I can find it myself.......thanks |
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Mrav8tr Samba Member
Joined: March 18, 2009 Posts: 187 Location: La Quinta, Ca
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Letterman7 Samba Member
Joined: March 14, 2004 Posts: 3198 Location: Downingtown, PA
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Posted: Sat Jul 24, 2010 6:08 am Post subject: |
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http://www.cbperformance.com/carbs.asp
That's a real basic starting point for sizing the jets. My feeling is that the motor may run rich at idle with the 50 idles, but they can always be tuned down with the mixture screw. I don't remember what I'm running currently, but it wouldn't matter - my engine isn't an aircooled, much larger displacement and has dual DCOE's on it.. |
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MURZI Samba Member
Joined: August 25, 2005 Posts: 5063 Location: Madisonville, La
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Posted: Sat Jul 24, 2010 6:40 pm Post subject: |
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115 and 50's should be spot on. Adjust the floats to 10.5 -11mm, fuel pressure to 3psi and then adjust the mixture screws 1/2 turn out from rpm drop. Finally sync the carbs. 130-135 main jets will be waaaaay too rich. _________________ 62 vert
2276
Tim’s welded heads
45 Dells
A1 sidewinder
Fk44 cam |
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Art3358 Samba Member
Joined: August 29, 2009 Posts: 1 Location: Palmdale, ca
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Posted: Sun Jul 25, 2010 5:09 pm Post subject: |
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I have the same issue with the same jets. Bugs are new to me as well. I took the plugs, and jets to the local bug shop. He told me the plugs looked good. The main and idle jets are ok. He recommended I change the emulsion tube to a F7 and the air jet to 180. The air jet was 200 and am not sure about the emulsion tube. It is in the buggy. I have parts on order. Should get them installed next weekend. i will post. |
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madmike Samba Member
Joined: July 11, 2005 Posts: 5292 Location: Atlanta,Michigan
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Posted: Wed Jul 28, 2010 5:22 am Post subject: |
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To the nybuguy,check out what size vents are in them too, U say it feels like it holding back,Maybe need 30's if ther 28's in them,But Float level and fuel pressure is critcal on Webers,like Murzi said _________________ 'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works" |
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