Red Pepper Racing

BEFORE YOU START: It is recommended that your car is already running good!!! Fix what problem you have before attempting the Devac - It will make having a good running car at the end easier.!

Also it is highly recommended that if you had problems before or can't figure something out to rebuild the carb, it is twenty some years old.

To educate yourself a bit more, link on carb parts and rebuilding it (not specific to 1st gen CRX or 3g Civic but still honda carbs of about the same year.):

http://www.3geez.com...read.php?t=5350

Some additional info links of others:
Scoobiewrxsti devac thread
HONDA KEIHIN CARBURETOR REPAIR
Darkhand Carb mods

Bike Carb setup info:
Bike Carbs
EuphoricBlue bikecarb How- to

Side Drafts:
Official Side-draft mikuni/weber thread - OG Wagon

Weber 32/36 install:
Weber 32/36 - ydennek

I am now in the process of doing a devac, and i'm having alot of trouble finding solid answers, and a good write up as to how to do it, i've searched through everything. So since i am in the process of doing a devac i may as well do a write up. Now i want this write up to be as detailed as possible, with pics, everything so that even someone who has never modded a car can get it done. Also it would help me devac my own car correctly. So i have several questions, and if you just have ANY tip or something that you found interesting, or anything from experience please tell me!

This first pic is my 100% stock engine bay before i started the devac. The red circles show the two black boxes that i removed and all the vacume lines that where connected. The green line shows where the one vacume line from the dizzy to the carb would run <-- more on it later.



These next pics are what i modeled how my carb should like when devaced (if i am correct they are CRXfantic's pics, i hope you don't mind)


1. This one is from the front view of manifold with the carb, it shows two yellow vac caps on, two block off plates, and three vac lines connected together, brown circled one, blue circled one, the third is on the next pic.



2. This pic shows the right side of the manifold with the carb, it shows where the third vac line is connected, with a yellow circle around it. it shows five capped places, one yellow all the way on the lower left one on blue the mid right, and then three bunched close together (top right), with the yellow closest and two blues right behind it. the port that has the blue tape on it is the fuel line <--- don't cap! or just keep fuel line attached.



3. This pic shows the rear of the manifold and carb on top. It shows seven capped ports, a blue all the way on the mid left (same as previous pic). Then on the top mid, there are three from the previous pic that where all bunched together, left to right: yellow, blue, blue. Now right in the middle there is one red cap circled in a light brown color (question about that one later). right under it there are two other yellow caps.



4. This next pic show the left side of the manifold and carb on top. it also shows six vac caps, same three bunched together from the two previous pics, two yellows on mid right from the first pic and one blue above it also from the first pic, i have to check but i'm not quite sure if the yellow directly to the left of the right blue cap is also another vac cap. There is also two wholes that i circled in green all the way to the left.



5. This last pic shows the top view of the carb and the manifold. with eight vac caps, two yellow on the left, top mid has the two blues and one yellow, right mid has one blue, bottom mid has one blue and one yellow. it also shows where the three vac lines are connected with the "T" in the middle.




Now when i did my devac i capped, and connected everything exactly according to this, i even have the same color caps for each part, so in essence this is how my carb looks like in my engine bay except that the manifold is connected to the engine and the fuel line is connected. One of the most informative threads that i've read is this one:
http://www.redpepper...e...20idle&st=0

So now some questions:

- in picture 3 (rear view of the mani and carb) it has the red cap, from what i read isnt that the "gas tank vent line"??? wouldn't capping this lead to bad flooding, and strong smell of gas? well it happened to me.. my carb overflowed with gas so much that i could see half an inch of gas in the carb. So should this just be left open?

- In the last 4th pic (left side of mani carb) i have the two out lets circled in green, if i am correct this is the "fast idle diaphragm" should this be capped? quote from DarkHand: "With the car running, connect a vacuum hose to that fast idle diaphragm again, just the port on the right (looking at the carb from the angle in that last pic), and suck on it! While holding vacuum, blip the throttle a little. This will make sure you're off the fast idle cam in the carb by applying vacuum to the diaphragm. The left port (further from the carb) turns fast idle on, the right side (closer to the carb) turns it off. If still no luck, try holding the choke plate completely open and blip the throttle... Perhaps the choke isn't opening enough." <-- very helpful but when i tried my high idle (2800-3000rpm idle) seemed to become unsteady and go lower then higher and back and forth, so i don't really understand the correct procedure for turning off the fast idle.


- Now i'm wondering about the places where the remaining vac lines should be connected, in pics there are absolutely no vac lines going to the dizzy, should there? also should it be hooked onto the top or bottom place on the dizzy? like this??:


green shows the vac lines, blue the "T"



is there anything that is capped that shouldn't be? or something that isn't capped that should be be?? Any info would be be highly helpful

also, the purpose of the devac is to: make the engine bay alot cleaner looking, better fuel mileage, maybe a bit "peppier" feel? is there more? is this correct?

Also i heard that i have lean out the fuel/air mixture, but i first want to know that everything is where is should before i start playing with that. This is kind of like a rough draft, hopefully with good input i will have enough detailed information to then make another thread with a detailed step by step how to devac.

I hope that this thread will have many pics and be very informative and help other with their devac job instead of stumping around blindly for answers.

Thanks for the help!
Edited by anassa, 05 October 2009 - 11:03 PM.

I will be watching this thread for input. I am also in the midst of a devac and am having issues. It sounds like your car is running after your devac, correct? Mine is not. Since pulling everything and capping the ports, I have not had any time to figure out what's wrong, but a few other RPR members are pretty sure it's the mixture. Like you, I want to make sure my capping is 100% correct before I mess with adjustments.

Sorry I can't offer any help, but I'll be sure to add input whenever possible.

Mike

thanks for the support man, i just hope some of the more experienced members will be able to help, and in turn help whoever else in the future will be devacing.

Thanks for referencing me/my pics. No worries, that's why I took them.

I sold the assembly as seen in the pic... when the buyer got it, he bolted it up and went, according to him.

Cleaner, yes; a bit more power, yes; better mileage, definitely not, by my experience.

All I adjusted was idle. It was fine after that.

Pic 3: The monster outlet on the driver side of carb (pic 2) is the one that made my carb flood badly, hence the reason it is left open. I believe it went to the charcoal canister.

I never ran the vac line to the distibutor. just crank alot of initial advance and go.

I know for a fact that many ITC racers who run the stock carb remove all of that fast idle valve and choke garbage. Unfortunately, I removed pics of this from my gallery. I have done it, too, but have not run it on a car, so I have no feedback. Mikuni PHHs came into my possesion before I had a chance to test...

ok.. i'm lost.. i've tried everything and it suxs, i first left the "monster outlet" open, i started it, and it just jumped up to 4500rpms and died.. played with the idle screw still no luck... then closed it, seemed to be getting better, but then started to idle crazily again, and kept on dying. then it started to flood again, i'm getting very frustrated cause its my daily driver and i havn't been able to get it road worthy for two weeks, soi've had to borrow other peoples cars, so then... more questions:

- "I never ran the vac line to the distibutor. just crank alot of initial advance and go." srry for being a nub but what do you mean by "crank alot of initial advance"?

- so no vac lines where run to the dizzy, does this mean that you just left those ports open? or capped off?

- lastly i thought i knew how to change the air/fuel ratio.. but now i have no idea, is it the second screw on the right (driver side) of the carb? it looks almost exactly as the idle screw, (you can see it in the pics). and then how do i know if my air/fuel mixture is correct? (other then installing a gauge of some sorts that tells me how it is.)


i know theres gota be guys out there who have the answers... please help. thanks, also even if you just happen to know any kind of random fact that you may of thought of just throw it in, it may just help.

Advance the ditributor timing until it pings then back it off a few degrees. Leave the 2 ports on the distributor open or closed, it doesn't matter.

How would you know what the a/f ratio is without an a/f meter or wideband? You simply must have one or the other unless you want to go to a dyno and get readings there. Any which way, it's gonna cost. You can just play with it, but you will never really know. I never f'd with my ratio.

OK just a small update. seems like there was a vac leak that caused the high idle. now it runs, i even drove it around the block, has nice throttle response, seems a bit more "peppy", but it seems to run weird, first its pretty loud, it sounds like an old school muscle car, like my neighbors 11sec muscle car, really rough and lumpy, so thats kinda weird. Second when i start it up there is a ton of smoke, then it dies down a bit. Also its harder to start the car, especially after i have already started it once, i think its still flooding. Also I think i have to advance the timing but again as a beginner i'm having trouble find out how in the world i'm supposed to change it. But it runs!! now i just gota get the bugs out and then it will be sweet!!

blah
Edited by anassa, 20 July 2008 - 06:00 PM.

Do you own a FSM? If not, you should. Not to be an a-hole, but I can't believe you undertook this devac project and you don't even know how to adjust ignition timing.

Service manual: Once again, convieniently located at the top of page. Quick link.

its ok, CRXfanatic i have a tendency to get ahead of myself, i've havn't even really had an interest in cars till about a year and a few months ago when i got my first car, the 91 CRX. i moved to So-Cal from a different country where a car wasn't necessary at all, so i didn't grow in So-Cals car culture. But i love to work with my hands and learn stuff, also i can't afford to bring my car to garage or something cause its too expensive and also its alot funner (<--- is that a word?) to learn myself. Thanks badpenny for the link, i'll bookmark it, and no i don't have a FSM (Factory Service Manual if i'm not mistaken), and i'm assuming from your reaction that i probably should get one. Sorry for my ignorance i'm just trying to learn . And white smoke coming from the engine bay and exhaust means i have coolant leaking into the engine right? would this be a headgasket problem? i just want to verify that before i attempt to pull the head. . . ya mabye i'm getting WAY ahead of myself.

No worries. Yes, FSM = factory service manual... Use the one RPR provides, it's free!

White smoke generally indicates coolant burning. Check your coolant and oil for a chocolate milk like substance, and smell the smoke, it should smell sweet.

thanks for the tip crxfanatic, i got my crx at my parents place now, and i see them on the weekends so hopefully i'll check for that and i'll update accordingly.

i wish you a lot of luck...i devac'd my 86 in feb or march and it's not run since...i bought new manifold spacers...ordered 2 new rebuilt honda carbs and put 3 known and good working weber 32/36's on the car still could not get it to run...it starts and idles but when you take it on the road when it hits about 4500 rpm's that all she wrote...it stalls, backfires etc until you back off the gas...i rejetted a weber thru the entire range of jets, etc and it's always the same problem...hiy hi rpm's and she stalls

i've never been able to drive the car as long as i've owned it ans have not been able to find anyone that's willing to work on it for me...so she sits covered in the back yard

Wow. Sounds like a fun ownership experience. If you're tired of futzing with it and the car is otherwise in good condition, I'm sure someone here would be interested in it.

If it makes you feel any better, I did the devac to mine a while back (December), and it hasn't run since. Of course, I haven't had much time or warm weather to figure it out, either. I'll get to it soon, as it should be warming up outside.

I'm thinking of changing to a better intake setup anyway.