Carb Conversion...thoughts, ideas?

[casey83civic]

Owned since new a 1983 Civic 1500 automatic hatchback now with 123k miles. Love this little car. Year or so ago had carb problems that the mechanic wanted over $1k to fix. I took upon myself to rebuild the Kiehen carb. Started up fine but rpms went between 1000 to 2000 rpm. Probably messed up or cracked a vacuum line. After Feb 1, 08 the Civic will be over 25 years old and does not need to get the "bad breath" test by the DMV.

That being said, I have thought about not messing with all the emissions crud and convert the carb to a Weber 2-bbl downdraft. That would mean pulling out all the bs vacuum hoses and cutting out the cat.

I have found a little bit on this type of conversion but would like to learn more from those of you who have actually been through the process.

I am open to any thoughts or ideas anyone can share with me.

Thanks, Casey

[Christ]

remove the cat, replace it w/ a test pipe. (ebay has a bunch of them)

pull the carb off, carefully, follow all the vacuum hoses back to the IM or sensors, and remove those things they're attached to.. you'll need to plug the nipples that the vacuum hoses connect to, and use pipe plugs for the holes on the back of the IM where those vacuum valves are.

Once you've done that, (or as you're doing it, if you can multi-task) take any sensor that you've disconnected/removed, follow the wires back as far as they go, and remove them. (to keep it clean)

other than that, take off the old carb, bolt up the new one, start it, and tune it from there, just remember that w/o that cat, you've got almost *no* backpressure, unless you have a really restrictive muffler on there, so you'll need to tune for having less backpressure as well.

[Christ]

BTW, it's nice to see that someone has owned the car since new, and still wants to modify it, this far down the road.

[casey83civic]

Thanks, appreciate it! It is still a sweet ride and it would be a shame to get ride of it just because of carb issues. We even still have all the pamphlets, Maroney sticker, purchase paperwork, owners manual....everything associated with this vehicle. Had thought about doing a stock redo of this vehicle but even after all is done it still will not be worth a ton of money. It does mean alot just to keep it to get it running better since the body is straight.

[Christ]

I don't see too many *PERFECT* 1st gen CRX's going for much more than 3-4k, and that's like the high limit of what I see... avg is probably closer to 1000-1500, and that's for almost mint.

The bullfrog look kinda kills it unless you grab a Honda Enthusiast, or a 16 year old that knows everything with so much more to learn.

I sold my first 1st gen for $1600 to a 18 year old "collector", and it was completely redone before I bought it for $400, just needed an engine.. I bought a donor car for $100, kept everything stock, replaced the clutch ($98) and sold it for $1600 w/ a full tank of gas, back when it was 2.30 a gallon.

So figure I made around $1000 on that one, but I would NEVER expect to do that again.

[casey83civic]

I agree with you. The car has been good to us all these years so we want to be good to it.

I have rebuilt the Keihin carb. The car starts and runs but the rpm surges on idle...and has crappy acceleration. I have the feeling that there is a bad vacuum line somewhere. With a car this old the rubber in the lines have to be bad somewhere. Gonna replace them and see what happens. Would like to do this first...but will consider doing a Weber conversion is need to.

Thanks, Casey

[Christ]

yes, all the vacuum lines should be replaced, you can get a silicone kit from Advance or AutoZone for like $15 that you cut your own lines from, blue or red.

Do a compression check, since you'll be right there anyway, and check/replace the plugs wires too, just a basic tuneup.

[aquarius]

yeah i gotta 85 rex and the factory carbs are a apain been tweakin on mine for a year tryign to get it to run right cause i dont feel like buying a weber cause they can eb pricy but eventualy i wil end up with one good luck with it all adn just make sure you dotn have any vacuum leaks and welcome to the forum

[Christ]

was all that actually a post? I couldn't understand that until I read it the THIRD time lol

Seriously, these carbs aren't hard to tune... it's just breaking the seal on the screw, and making sure that all your bases are covered.. IE, gas is good, carb bowl is clean, etc.. it's just like tuning any other carb. I've laughed at ppl numerous times when they say "this carb is picky... it only likes to work when you turn the screw REALLY slow.." or something like that..

If it has a problem, and doesn't act like EVERY OTHER CARB THAT'S EXACTLY THE SAME on the market, try fixing it.

[cvcc_wagon]

the 1500 EM1 motor is a cvcc motor, which means it has a 3 bbl carb on it, you will have to allow the third barrel to breath, it's the dime sized one on the front that sits lower on the spacer plate.

what do you mean "rpms went between 1000 to 2000 rpm". describe this better because it sounds like it could be a problem i had once