Well I had a carb that would do that, if I understand your meaning. The float bowl vent solenoid was sometimes stuck due to a slight buildup of gum and varnish. So I removed it (19mm wrench I think), pulled the spring and reinstalled. Now it's open all the time whether it's powered with 12V or not. It was a carb that had been sitting for probably a decade.

This carb was super sensitive to flooding before. By flooding I mean it would flow gas out of the secondary boosters and fill the barrels. Of couse all this fuel would make its way down into the engine, then down into the oil pan. Now that I messed with the carb a bit, it doesn't flood anymore. I left the spring out though. It's a boost prepped carb with a carb hat so the gas fumes aren't going to leak out into the atmosphere easily.

 

That sounds plausable. Just to verify my meaning though, when this carb is hooked up everything that flows into flows out of the fuel bowl purge bung and whatever that can't keep up with is pushes straight into the carb and into the engine. If that sounds to you like what you just described then all I ask now is do you have pics before I break everything?

 

100% instant flooding there. The purge vent is just at the top of everything, so fuel coming out of it just means that the reservoir it "vents" is filled all the way to the top, causing it to spill over. It is funny though, as usually it fills the carb up with gas first (atop the butterflies)

 

Is that still the case even when I have the floats set so the fuel level is at the halfway mark on the sight glass?

 

Maybe your solenoid is stuck closed like mine was. I'm running out of ideas.

 

Well my guess is it was the mechanics side of the solenoid. I took it apart and cleaned it all with brake cleaner and a wire brush and it works now. Now just to get it tuned and running right again. Thanks for all the help.

 

And no matter what adjustments I make I can't get it to idle. If I have the idle screw any where but all the way out it wont even rev, it wants the mixture screw almost all the way in, and it backfires the whole time through the rev.

I think I'm just gonna treat this carb as scrap and just try to strip down my stock one.

 

You need to know what you're doing when you modify carbs; I'm talking about the SVT guy here. You need a deeper understanding which I think Yaw had. Sterling had an "ok" understanding but I think he still missed some key points. I'm still learning about these things myself and won't claim I know more than I do.

You might not need to junk this carb unless it has some actual hidden damage somewhere. I just threw away two water damaged carbs today that were beyond help. I stripped off all the good bits then gave them to a metal recycler.

My first hogged Nikki had idle problems. The mixture screw was useless. Then I swapped in some different primary slow air bleeds that I drilled to .046" and it made the screw useable again so when I'd turn it, it would have an affect. If the SVT guy essentially copied Sterling, who also had unsolvable idle problems at times, then that makes sense.

Maybe your primary fuel jets aren't the right size. I bet they're holley air bleeds because the thread pitch is almost the same as stock metric jets. This is what Sterling used. I just use stock jets in mine drilled to .046" and it works with my slow air bleeds drilled to the same size and matches my hogged venturis.

Your carb might have a twisted shaft too, if the SVT guy took it out and machined it. This is something I won't do.

Oh well, if you do decide to sell the carb, maybe someone on here would be interested. Heck if you shipped it to me, I'd take a look and maybe get it up and working again. Or diagnose an unfixable idle problem or something. I dunno. It's your carb and you're in charge of its fate.

 

I might just send it to you.

I'm not too worried about it now but I'm fairly certain my stock nikki has never seen a rebuild in its life. While working on this POS I decided I should soak my stocker in seafoam so I force injected through the fuel rails and then made it cycle into the carb like normal. Let that soak for about 2 hours and now the stocker loves life alot more. Hopefully this'll last till I find that Mikuni I want and then give me some time to rebuild the stocker.

 

If you do send it and pay shipping, I will work on it for you and see if it can be corrected. Then if you pay return shipping, I'll send it back. I'm mainly curious to see what this guy did. Maybe learn a few things.

I've got a wideband and a blow through nikki setup over here to test it on. If the engine is unhappy with this carb, I will know right away before any damage occours. Heck I tested the racing Nikki which had some serious setup problems caused by the previous owner, and the engine was happy as can be when it wasn't flooding itself. I might even complete the job on your carb where I do the Sterling style accel pump mod and stuff. You know, whatever it takes. If you pay shipping both ways, we're good.

Hmm, I wonder if this should have been sent to PMs. No, I want a public record of this.

 

Thread update.

Jingkun did send me his carb. And I was absolutely floored by the massive glaring incompetence. Never have I seen such a pisspoor job. Everything that could be done wrong during a carb rebuild, was done wrong. I'm speechless... should have sent a poet. I don't have the vocabulary.

Basically every part of the carb this CobrastngSVT guy touched was quite literally ruined. From a bent primary shaft on both sides, to mared and damaged screws holding the throttle plates in, that weren't even tight! The engine could have ingested one. They were crooked and needed to be resintalled straight. Then I used some red loctite to hopefully keep them in. Also the secondary shaft was thinned and the screws he cut were sharp at an angle and needed to be trimmed. I ground them down with a dremel.

I'm just getting started. He used an air powered scuffing pad and took off all the rust protective coating, seen in the picture below, from the cast iron baseplate. Turned out to be from a water damaged carb, which Jingkun said he didn't send, so looks like he got a lesser carb back than one he originally sent. Sounds crooked to me.

Speaking of which, there was some kind of thick glue on both sides of the base plate that caused the carb to sit crooked and allowed a vacuum leak. I box-cutter-razor-bladed that stuff off and had to use three baseplate gaskets to try to prevent leaks between the base plate and main body. I fear it was slightly warped by him so I did what I could.

There were glass beads and rust in the idle circuit! No wonder this carb couldn't idle right for Jingkun! That, amoung many other reasons.

He glassbeaded the main body too. There were glass beads EVERYWHERE!!!!!!!!!!!!!!!!!!!!!!!!!!!!

You can even see lots of them in some of the pics Jingkun posted last year, like up in the float bowl vent opening in the air horn. It looks like dust but nope, all that stuff was glass beads. Or at least some kind of media he blasted it with. I'm sticking with calling it glass beads. The secondary vacuum box channel was full of them too. The fact they were never cleaned out makes you wonder... I cleaned them out the best I possibly could with every tool I have around here.

His accel pump was drilled WAY TOO BIG and he posted pictures on his other thread so I won't bore you. Look here for incompetence masquerading as skill, and all the hangers on. So very sad. People realy were desperate for modded Nikkis I guess. Or far too trusting, after Sterling paved the way. https://www.rx7club.com/1st-generati.../#post10858669

The Sterling flip-o-matic sucks ***! It opens the secondaries too far and they begin to block air flow. So I put it back and welded it like I do on all my boost prepped Nikkis. Why? Because I boost prepped this carb for Jingkun and included enough tuning parts for an NA tune and a boost tune, for his future aspirations. I don't trust a simple wire tie with boost. And I had to fix the flipant-o-matic. I couldn't leave it like that.

Let's see... Oh that SVT guy got powdercoat all over the threads and the steel core of the float bowl vent solenoid, rendering it frozen in place and useless to prevent flooding, as Jingkun struggled with. The idiot (SVT guy) also forgot to install the spring, not that it would have done any good, being stuck like that. Oh he attempted to scrape some of the powercoat off the steel core, but it didn't do any good. So I did my standard complete gutting of the FBVS like I do on all my boost prepped carbs so the incoming boost signal has a way to get into the float bowls. Still works fine for NA too.

The float bowl vent was filled with quicksteel, as was the secondary vacuum diaphram box' hole on the side of the carb. The lever was frozen in place so vacuum secondaries would never have worked anyway.

The fuel rail was installed with the wrong crush washers. He forgot one of the other crush washers, and it leaked in another area. Doesn't take an Einstein to get this stuff right. I'm no Einstein and I've gotten it right every time.

The needles and seats are out of a standard rebuild kit. I should know. They are the crappy incorrectly machined ones that ALWAYS lead to flooding. They should never be installed during any carb rebuild, but idiots and folks who simply don't know, always do.

LEAVE THE STOCK SEATS ALONE!

Remember Sterling always said leave yer damn floats alone. Remember that? My contribution to the leave Britney alone fund is to just leave yer damn OEM seats alone. I had a dickens of a time getting this carb to not want to flood out constantly. Blackened up my spark plugs pretty good. Unfortunately I don't have any OEM seats for his carb. Otherwise I'd gladly donate them.

The boosters were poorly modified by him. I decided to give them (all four) the airfoil mod but otherwise left them alone as a reminder. I posted one pic of both primaries sitting in a container waiting to be installed and you can make out the sharp edge.

Anything else wrong with this carb? Hell yes! But I think I honestly have forgotten most of it by now. I just wanted to move on. This carb was way too depressing to work on and correct every part of it that the idiot touched.

Oh every screw head was damaged. Not just the throttle blade screws but all the other screws. Even the threaded holes had wrecked threads. I chased out what I could and they all work now. I also swapped in some screws from another carb, or I hammered the heads lightly to reshape them so they would hold a screwdriver tip again. That idiot said he would smack each screw with a hammer to loosen the 30 year old seal. What a dork. He should have tried a slotted or flat head screwdriver before resorting to the incorrect US-spec phillips on a J-spec screw. Yes it's true. There is a difference in the angle of the phillips screws. I'm not making this up. So I only use a phillips to spin them in or out, but I tighten or loosen them with a flat head. It doesn't take an Einstein... But it does take an impact screwdriver on a couple of them, which this idiot clearly didn't own.

Speaking of screws, I did the Sterling accel pump mod and drilled a banjo bolt and nozzle to 118 like I always do. This 118 or 1.18mm or .0465" bit is a lot smaller than the idiot used. I guess no one ever told him that too large of a hole would cause issues, eh? Oh and I swapped in some new screws and a stack of gaskets to the accel pump diaphram housing. Turned out nice.

Ok the next part I was saving for last. It's about the venturis this doofus cut. For some reason he thought that cutting from the top was the right way to go. His goal was to reach 22mm from the stock 20mm. It moved the narrowest part of the venturi to 9mm below the bottom of the booster. You know, I looked at a Holley, and an Edelbrock, and even a stock Nikki. Guess what? All of them have the narrowest part about even with the bottom of the booster. What was this SVT guy smoking? How on this planet or any other, did he think such a deranged venturi would work? He either lacked any kind of insight into carb theory, or he just wanted to make a quick buck on a boat anchor. How can anyone be that stupid? Or crooked? He was charging 400 for a carb that didn't even run!

Before I set out to correct this obvious mistake on his part, I test ran the carb. At the time the idle circuit still had glass beads and rust in it, unbeknownst to me. Whatever. I just wanted to see if the dang thing would run.

Oh it ran all right. On the only circuit I had addressed at that point which was the accel pump. It would start right up, and you could keep it running with your foot at like 3 grand, where there is so much air moving past the worst cut venturis in existance, that it would kind of start to work. But as soon as you let off even just a tiny bit, it would stall out quickly. It would start right back up again with a couple pumps of the pedal, but it would only run for a few seconds each time.

So I did the only thing I could do. I cut a set of my own venturis from my own collection. Basically my last spare set. I cut them to 22mm, because that was the same ID as the junk ones. Pics below.

I wonder how many other poor souls were taken in by that charlatan. There's gotta be a few. Anyone care to talk about it?

Anyway, enjoy the pics!

 

Three gaskets stacked.

Main body warming in the sun, waiting for the 22.3mm venturis to go in.

Installed with a boost tune for testing on my setup. It'll go back to an NA tune when I'm done.

Complete, ready for testing.

 

Oh one more thing I forgot to mention. After I cleaned the idle circuit, I swapped in some stock 20mm venturis and test ran the carb again. It worked!

So by undoing two mistakes the idiot made, the carb was finally on the right track to becoming something closer to what Jingkun spent his money on.

But he was really only interested in a carb that was hogged out, like a Sterling at 22mm, but didn't want to wait 6 months for one. So he bought into the SR Nikki band wagon, and was burned hard.

Look, I'm not selling anything. This is not a service. I just, on whim last year, suggested that if he pays shipping both ways, I'll take on a basket case carb and see what I could do with it. And so far I have delivered. The dang thing actually runs now.

But what Jingkun really wanted was a hogged out Nikki presumeably to 22mm like a Sterling or the junk SVT size, which I decided to see if I could do. As you can see in some of the pics above, I think I did an ok job. They're the ones that came out to 22.3mm, which I wrote down with a fine tipped sharpie. They took only a day to cut by hand since I lack a lathe. I also cut mine from the bottom up, as you can see. The upper part is left alone. This is 180 degrees opposite from the SVT guy's approach. If I could get in and adjust the upper part, I would, because as you can see, the little hole is now below the narrowest part. However I have not found any real problems doing it this way. Sure it's not an ideal textbook venturi shape, but it's darn good. Heck one of my boost prepped Nikkis cut even larger to 25.6mm was able to break them loose in gear on dry road on primaries only! So if that doesn't say good things about my bottom-up approach, I don't know what does. I don't recommend venturis that large though. Especially on a 12A. But these 22.3mm ones should be amazing on a 12A and I'm sure they'll work great on my 13B when I test them.

Oh yeah one more thing. I had to correct the throttle lever linkage. It was all out of whack and bent here and there. Also threw in my very last return spring and bracket. That is why it's not powdercoated. lol

 

Kind of explains why he dropped off the forum. Shame.

Nice work Jeff, I hope Jingkun appreciates it, a lot.

 

Thanks. Yeah, just be glad you chose to mod your own Nikki instead of buying a boat anchor from this shill.

According to a later post by Jingkun, a thread directed at the SVT guy or one started by him was apparently deleted to protect him or his business. Then there were never any complaint threads from any of his customers accept for this one by Jingkun. Maybe it's not technically a complaint thread, more like a what do I do now thread.

I think a little editing was done quietly behind the scenes. Or did Jingkun just get a bum carb? Or were they all like that? The world may never know.

I'm going to see about testing his carb today. I'm going to swap the top from one of my recently aquired untested carbs that has OEM seats because I can't have anymore carbon build up on the rotor faces and seals from crappy aftermarket seats allowing constant flooding. I think one of my engine seals started getting stuck after the adventure of last week. And it gives me a chance to test an untested top from a carb that's getting rebuilt and boost prepped. All the work's been done to the top such as choke shaft removal, alt comp blockoff plate, filled the little 40 air bleed with solder. Filled the FBV nipple with quicksteel along with the choke shaft holes and removed the FBVS steel core and nylon valve. Now all it needs is to put some gas through it to see if the rescued fuel rail I had to install will be fuel tight. The PO removed the original rail for some reason.

Imagine that; the crappy SVT carb is now good enough that I can do a little additional carb testing with it. Man it has come a long way since it first arrived!

 

I have an awesome update. This carb likes boost! No secondary delay! It didn't want to flood at all! It ran at a good AFR in primaries and secondaries!

I could just leave my foot into it as long as I wanted to, to like 8 grand, and it didn't complain at all. Accelerated cleanly and easily broke them loose in gear on dry road even in warm weather. Kinda wanted to in 3rd gear too. This carb is amazing now!

The drivability is quite good. Great low end. Great part throttle. Great response when you floor it and also great tip-in.

That was the good news. Now on to the bad news.

The accel pump, while good, sometimes doesn't squirt. Like it has a bubble in it. Then again this carb was built in '11 so it's kinda old and it did sit dry for a while. Maybe the diaphram is a little stiff. It should soften up over time and exposure to gas. Or maybe too much OMP oil, not getting down where it needs to be, is causing issues.

The OMP nipples were shortened by the idiot. This lets oil kind of go wherever it wants to, but doesn't get down into the engine very well. I think sometimes a massive glob of oil pools up and then gets sucked down the carb all at once, leading to a weird carb glitch or running issue that lasts for about a second. I didn't think to look out the back for any smoke when it did this. It happend maybe twice during test driving. This is something to be aware of .

One more issue I noticed is when I would take a corner. The engine's RPM would go down a bit. So I looked at the wideband and it showed a rich condition. I've never seen this before on any of my Nikkis so it's a new one to me. It might be caused by my airhorn. Maybe the floats aren't quite right? But the fuel levels were in the middle of the windows. Hmm.

Yes I tested the carb with my air horn. There was no way I wanted to fight some crappy aftermarket seats while testing a carb for boost. Those aftermarket ones will need probably 100 miles to break in. I obviously didn't have that kind of time or inclination. I needed something that could work right away so I could get the testing done today.

Now to general info neither good or bad.

Starts pretty easily but you do need to keep your foot on it due to a lack of a choke.

My best guess turbo tune was pretty much perfect. AFRs were high 12s to low 13s at part throttle cruise. Boost was 10 to 11 or so. The idle is right where my engine likes it at 12.2 or so.

Then I swapped in the NA tuning parts and it's a tad rich due to a lack of Holley air bleeds in the right size, but it's still better than what the idiot included.

The idiot had 140s in the primaries. Way too big! My turbo tune used the 114s. It was perfect. The NA tune needed to be richer so I went with a set of my 129s and it's a little rich but better than 140s. Yeesh.

Mathematically speaking, I would say jets around 122 to 125 for NA use would be just about right.

 

Another huge mistake the idiot made was in the way he machined and ruined the main air bleeds to hold Holley air bleeds. All four were drilled all the way through, thus allowing the little emulsion tube to fall off. Then he'd press them back on. It would crush the solder glob at the bottom, which flattened it (my first clue) then when I applied pressure to one of them to check, the solder broke and went up into the e-tube. So then I checked the total length compared to a stock one, and sure enough they were shorter than stock by a couple mm. You know what that will do right? It changes the calibration of the e-tube by having the lowest and also highest holes at a different location than stock.

The SVT guy was a complete idiot who lacked the most basic understanding. If any of you were duped into purchasing an SR Nikki, please give it to a metal recycler because there is no hope in restoring its functionality. Just kidding. But the truth is you will need to go through every part of the carb and undo everything the idiot did to it.

To correct the idiot's mistake, I provided a set of my machined adjustable air bleeds that were done correctly, or at least I didn't ruin them and then try to cover it up.

But in the end I discovered stock 70 air bleeds are perfect on the primaries and stock 140 air bleeds are perfect on secondaries if NA. If turbo, you can keep the stock 70 primaries but the secondaries need to be adjustable. Fortunately for us the secondaries are big and easy to machine.

Pro tip: Stock 70 air bleeds are actually smaller than the 70 stamp would suggest. They are more like .67 or .68mm. And guess what? The Holley 27 air bleeds the SR Nikki came with are .68mm so it's the same size in the end. So why go through the trouble of even modifying the primary air bleeds in the first place? There's no point. But as it's adundantly clear, brightness wasn't this SVT guy's strongsuit. However I understand the value in having adjustable air bleeds. I've just found that it's not necessary for primaries. So save yourselves some trouble. Leave your stock 70 air bleeds alone! Now if you have 60 air bleeds, you can drill them out to .67 or .68 if you really want to, and can find the right micro drill bit. All I have is a .64mm. Or if you have an SA carb that came stock with 90s, well, I don't recommend boost with these carbs anyway so lol whatever.

 

It really comes down to giving your RX7 carb to a man named "CobrastngSVT".

I'd trust a guy named like "MAZ7GSL" or something along those lines.

 

As it came down to it I felt that giving anything rotary related to a guy with a name that corresponds to mustangs in any way was a bad idea to begin with, but I thought I saw alot of positive feedback at the time and, well, looking back now it was probably all just self promotion.

I more than appreciate this work that Jeff has done. Hell I appreciate the fact that it runs now and looks better than when I got it back. So many things have been pointed out that I would never have guessed at, like the dust that was actually glass etc.

Jeff has put an incredible amount of work and detail into fixing this 1 disaster that I apparently paid to have made and I can't thank him enough.

 

This is why I built my own "hogged nikki" lol.

Mines running perfect with plenty of power thanks to its 24.5 mm primaries. lil bigger than stock, but it makes a huge difference.

Honestly, if I had enough interest from the forum I would replicate it.

For now though, its just mine to have fun with lol

 

Same here! Love my hogged out nikki. I still have my Dell, maybe use it on another project.

 

What size did you go out to on yours?

 

Are we trying to determine whether 24.5mm is the best size to hog these out to on a 12A?

I just completed and installed a set of 24.45mm and another set of 25.35mm in a couple of 84-85 main bodies. The 25mm is for a 13B since that size seems to work ok with only a little glitch at around 1700 which you don't notice while driving. The other at 24mm was planned to be a spare for a streetported 12A or just general use whenever I need a carb for something like test firing a fresh rebuilt engine or something. However I'm starting to second guess going this large based on how nice Jingkun's 22mm turned out. It was overall nicer to drive but seemed to lack a little transient response on my turbo 13B. Probably due to its smaller size on a big engine. Your thoughts?

I have two more sets to hog out. I might try 23mm on one set and 22mm on the other.

 

I dont know, but the 24.5mm was actually a power upgrade from the holley 465. Not so with the stock sized nikki.

I also milled 16* inlets and its been perfect for me.

 

To tell the truth I never measured them. I just took a dremel and some large cotton
pads with valve grinding compound on em and went at it until they looked a bit bigger.
From the top side without removing the venturis. Sounds kind of primitive and it is
but seemed to work great for me. I have no complaints.