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-   -   carb swap (https://www.rx7club.com/1st-generation-specific-1979-1985-18/carb-swap-604163/)

workinprogress80 12-10-06 10:57 AM

carb swap
 
I am planning to do a carb swap and i was wondering what kind of carb i should use. the car will not be much more than a daily driver. maybe occasionally a race down a quiet road or something.

Kentetsu 12-10-06 11:03 AM

In that case, I would say stick with stock. Why are you swapping it out rather than rebuilding the one you have?

No_Rotor_RX7 12-10-06 11:05 AM

agreed, stick with the nikki. i've made lots of power on the stock carb... so for a normal daily car you really don't need anything more :)

flight_of_pain 12-10-06 02:50 PM

stock nikki with mech secondaries, and rats nest removed will work for quite a few more mods before it needs upgraded. a long tube header and better exhaust will really free up the power as well.

isaac

workinprogress80 12-10-06 02:50 PM

ive had many people tell me that i need to get the weber simply because it is easier to tune and it is reliable. also i tried to rebuild my nikki and it worked for a little while then it started flooding out. it also keeps pouring feul in after the switch is off.

workinprogress80 12-10-06 02:51 PM

what exactly is the rat's nest used for

Jeezus 12-10-06 03:10 PM


Originally Posted by workinprogress80
what exactly is the rat's nest used for

Emissions emissions emissions! remove it!

trochoid 12-10-06 03:25 PM

What other mods have you done so far? If you haven't done headers and exhaust, you are wasting your time with a carb upgrade atm. Sounds like you need to go back through the Nikki and do it again.

workinprogress80 12-10-06 04:26 PM

I havent done any mods to the car yet . right now i am trying to get it running first because i pulled it out of a barn where it had sat for about ten years. I do plan on doing a header and exhaust though.

bridgeit 12-10-06 05:51 PM

have fun driving that everyday.sounds like your lost
and tha car sat for 10years

flight_of_pain 12-10-06 06:22 PM

the nikki is deceptively simple, its all the crap thats attached to it that makes it complicated. if your pouring fuel from the mains, then recheck your float needles. if you didnt replace them when you rebuilt then check the screens around the banjo bolts too, once they go south the bits tend to clog the float needles.

isaac

Rx-7Doctor 12-10-06 07:09 PM

If you didn't take it completly apart after sitting for 10 years and let it soak in carb dip for days then you need to re-do it as Trochoid has stated. Even if you did, you need to take atleast the top half off and recheck the float level and replace the needle/seat if you did not the 1st time.

workinprogress80 12-10-06 09:03 PM

i replaced the needle and seat when i rebuilt it and i replaced the carb with one that i got from a guy that had not been sitting on a car, it was dry and completely spotless

Kentetsu 12-11-06 12:03 AM

So are you saying that you have had the same issues with two different carbs now?

Either way, you don't need a weber. Use that money for a new exhaust system (which you will probably be needing) and tune-up parts, brakes, etc.

Restoring a car that has sat for ten years will take some work, and some money. Be patient, and keep reading in this forum, and we will be here to help with whatever you need.

One more thing; Seafoam is your friend! Pick up a can, and once you get the car so it will run (or at least idle) dump that can into your almost empty (about 1/8) gastank and let it run through. This will remove everything from the engine itself that you don't want to be there. This is very important for any rotory that has sat for a long period of time.

workinprogress80 12-11-06 04:09 PM

Alright, let me get my story straight. Before i dug into the carb i replaced the feul filter, changed the oil, and got the gas tank cleaned out. after that i tried to start it and it wouldnt start. i pulled off the air horn and the rest of the assembly. i then took every thing out of the old carb and trashed it because it was full of some gooey stuff and i didnt know how to clean it. i was not getting feul any farther than the float bowls so i replaced the carb with a different one that i got from Chris Sneed at Sneed's Speed Shop. i put on that one and got a rebuild kit for it, now let me say that this new carb had been cleaned and checked for operation and it worked fine. so i put it on and the car ran fine for a little while i drove it up and down the street a few times to check operation of the clutch and brakes after i bled them. one night i took it out and went up the road and drove like a grandma. i only drove it about 100 yards and came back. when i got back my brother wanted to drive it and so i was going to let him. so he gets in and tries to crank it and it doesnt crank. it floods out so i pushed it out of the garage and tried to start it. it made a loud but muffled pop and smoke poured out of the exhaust pipe and then it would start but barely run and the feul would pour into the secondaries when the switch was on and then for a little while after it was off. so i took out the plugs and all of them except one had a crack inside the porcelain inside the plug. so what the hell is going on!

Rx-7Doctor 12-11-06 04:22 PM

The only way you are going to find out is to remove the top of the carb and check. It's possible that more sediment from the tank came thru the lines and has gotten into the needle and seat and it's stuck, not shutting off fuel after the bowls are full.

Midwest 7's 12-11-06 04:46 PM

get rid of that complex 4 barrel crap and get a 2 barrel.
mikuni 44phh, dellorto 48 dhla. 45 or 48 weber of various styles.
you can pick up a complete setup for $400 or so.
i always say the less parts to fuck up the better.
simplicity is your friend. :)

workinprogress80 12-11-06 07:49 PM

Alright doc i took it apart and adjusted the floats a little then put it back on and the feul was only flowing from the barrels on the side closest to the seats. What now

aussiesmg 12-11-06 09:00 PM

Did you turn on the fuel pump with the fuel line disconnected to drain the old fuel from the lines, I agree it sounds like bad fuel is blocking something in your set up, by the way I concur with the Mikuni on a stock port, but you'll need a good exhaust

Kentetsu 12-12-06 12:08 AM

Hmm, porcelain was cracked on the plugs eh? Well, that would seem to indicate an ignition problem after all. But with fuel running down into the secondary as well, it would seem that you have two issues (at least).

Start with the ignition. Verify that you have spark on the leading side, and if you are able to get it to run at all, then set the timing. Once you get the ignition straight, then start tracking down the carb issues....

trochoid 12-12-06 12:43 AM

Cracked porcelin can indicate a lean condition too. Did you tear down the carb completely, including removing all of the jets, air bleeds, the fuel supply off the top of the carb, etc?

Floats rarely need to be adjusted. Sounds like you missed something in the cleaning or reassembly. Also, when measuring for float level, the gasket is included in the measurement.

workinprogress80 12-12-06 05:58 AM

Yes i did tear down the carb completely when i rebuilt it and i also took into account the gasket when i did my measurements for the floats.

workinprogress80 12-12-06 05:48 PM

One thing I forgot to mention is that the new carb i put on it came off of a later year model. i was reading on the rat's nest removal and saw something about having different internals. this carb looked a little different than the old one. could that be the problem.


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