1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Tuning a 45 DCOE weber?

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Old Dec 18, 2020 | 04:23 PM
  #26  
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From: twisp WA
could you show me some pics ?
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Old Dec 21, 2020 | 04:46 AM
  #27  
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From: Lyon
No pics sorry, just leave it opened on the dizzy, and plug on the intake manifold.
To set advance timing, you need a light, you need to mark the pulley and set to the appropriate timing.

I believe there is a write up on this site somewhere.
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Old Dec 21, 2020 | 08:38 PM
  #28  
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From: twisp WA
ok is your distributor stockwith the vacuum ports blocked ?
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Old Dec 22, 2020 | 01:41 AM
  #29  
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From: Lyon
No, I just left them opened.
If you are afraid, you can put a small rubber cap on top.
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Old Dec 22, 2020 | 04:39 PM
  #30  
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From: twisp WA
I did all of that and re-timed my car but it still wont run right
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Old Jul 11, 2021 | 12:50 PM
  #31  
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From: CYPRUS
Originally Posted by Chamele03
i am using the stock fuel pump with no return, but i was told this would work by Rob at rotary shack, and have no clue what jets are in it, I told him my setup and he went though the carb to set it up for me.
rotary shack send me a carb for 950 usd with manifold and
he said will work on my 12a rotary but it does not and he never answers the phone.. after 3 years i am still trying to get it right
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Old Jul 11, 2021 | 03:27 PM
  #32  
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From: FL
welcome to the board.

just for the sake of clarity, when you say it doesn't work on your 12A, do you mean it doesn't fit at all, or it fits, but doesn't run right?

after 3 years, i am skeptical you could do anything about it if it's the former, but if it's the latter, then you should be able to get some help here. i'm not sure if you want to start a new thread or not, but just tell us what the car is doing (or not doing) and include as many details about the carburetor as you can.
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Old Jul 12, 2021 | 05:12 AM
  #33  
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From: CYPRUS
weber 45 on rotary 12a

weber 45 fits fine and starts fine but put your foot on gas and keep it there in 2000 rpm 3000rpm or 4000 rpm and you get this grirrrrrrrrr like wants more fuel maybe or i do not know. the car now is at the shop of a mechanic trying different jets and getting nowhere. it has a racing beat exhaust system as well. carter fuel pump 4070 malpassi fuel regulator..also new spark plugs br8 eq14 new ignition modules engine rebuild with new 12 a housings the last ones they had. if i post a video here will it help
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Old Jul 12, 2021 | 06:16 AM
  #34  
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From: Lyon
On low rpms (<4000) you do not want to put your foot fully on the pedal at once, you need to be progressive.
It lloks like you may have wrong jettings - or the venturi are too big.

I have 38mm venturi, and I cannot put my foot on the floor below 3500rpm - with 36mm it was possible but then I lose a lot power above 6000rpm.
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Old Jul 12, 2021 | 10:30 AM
  #35  
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From: FL
i tend to agree with the above post, you may be looking at a need to re-jet your carb.

i can't speak on jetting for the 45 DCOE because i never worked with one, but when i was tuning my Dell'Orto, a great deal of the issues i had were with achieving the correct fuel pressure. so maybe that is something to consider (or relay to your mechanic). i ran the same pump you have, so i know you're good with that. i haven't heard any bad experiences with the Malpassi regulator, so you should be good there, too. are you running a gauge on the setup, if not, you should. a little advice about the gauge though, i wouldn't put too much faith in the precision of it, so much as you should use as reference point. pay more attention to what the engine tells you and then make a note of what the gauge says.
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Old Jul 12, 2021 | 11:48 AM
  #36  
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From: https://www2.mazda.com/en/100th/
if you search i've posted a carb tuning white paper before, and it is nice because it gives a process to tune the carb. you start with idle work your way up. since you go in a series of steps its hard to get lost, or overthink things.

once the carb is right you should be able to floor it at anytime and it will go
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Old Jul 13, 2021 | 12:35 AM
  #37  
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From: CYPRUS
I would like to thank everybody here for there help thank you guys
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Old Jul 13, 2021 | 05:55 PM
  #38  
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From: FL
here you go:

j9fd3s' white paper thread: https://www.rx7club.com/1st-gen-gene.../#post12417710

48 DCOE issues at 3000 RPM: https://www.rx7club.com/1st-gen-gene...00rpm-1144899/
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