So i bought a stripped nikki here on the forums some time ago, and finally got around to testing it on a running engine I had to see if all the fuss was about.

Having built countless holley's at this point for the 12a I expected lower power output out of the nikki, but I figured it would make up for it in other areas as others frequently claim...

And the result is exactly that! I think I will start doing some mods to these in the near future, since basically everyone who picked up the torch after yaw is no longer taking orders...


But a few questions about this set up I havent been able to find any good info on here on the forums before I actually invest.

This carb hasnt even been rebuilt before, and already has better reliability than my rb 465 as delivered new, and is on par with my dyno tuned holley in terms of throttle response, MPG's and low rpm grunt. It DOES lack lack some high end power compared to the holley, but it has no surging, and no funny business at low rpms.

BUT I cant seem to set the idle where I want it... and I have the mixture screw backed out about 5 turns. idle stays around 1100-1300 rpm no matter how I adjust the idle speed screw. Is this normal for older nikkis? Seems to me its getting air somewhere, but I cant find it.


Checked for vac leaks, timing, and tried adjusting the idle speed as much as I could. If I firmly press the linkage in reverse, I can lower the idle to the desired speed, but if I let go of the throttle it just goes back up to 1100 rpm. Anyone had an issue like this? I know it screams vacuum leak, but I swear to you ive checked everywhere, and changed virtually every hose/gasket possible in the last day or so during install.

 

Seems I cant make a WTB thread for these on the parts forum...

 

The fact that you can press on the linkage and drop the idle insists that you have something in the linkage holding the throttle plates open too much. First, disconnect all throttle cables. Then turn the throttle stop screw all the way out and see if you can force them closed any farther by pushing the linkage in reverse as you did before. It'll probably take some close examination to determine what's catching.

 

I did that already, i think maybe the linkage itself is just bent up from ups...

 

I had the same problem as you, only if I pressed on the linkage in reverse the idle would come down and stay down until the plates were moved again.

I ended up taking the return spring and tying a few coils together with some string; essentially making a slightly stiffer spring and mine is good to go now.

I realise that before I did this turning the mixture and speed screws may have not even been doing anything as I wasn't even in the idle circuit entirely.

Hope this helps,
Kam

 

I pushed on it a little more and did some more tuning and got it down to 1000 rpm, but im still not satisfied. On the street this carb is amazing! I love the sound of it when it opens up with the RB breather. It needs a rebuild but im highly impressed with its design.

If I can locate some of them I will get to work on some of the homework on performing the mods as a service, sorta like the holleys ive been doing

 

did you get it working (wankel-awsome)?

Does anyone nowadays rebuild the nikki?

 

I bought a rebuild kit from a mail order parts site based in Toronto, it was actually a lot easier to rebuild than I thought it would be....
Mind you, I psyched myself up for it and had egg cartons, baggies and took something like 200 photos of the process so I would be able to back track if need be.

Kam

 

Those who wish to have them functional! It's so easy even I can do it.

 

Yeah they're not too bad to rebuild. They just have a lot of clutter - almost all of which can be removed.

 

has anybody entirely figured this out entirely. im having the same problem.

 

From what I gathered from my issues it was a weak return spring. Maybe fatigue?

Kam

 

One day on my last rx7 I got tired of bringing the carb to my friends. Started taking off screws next thing I know I have the top off. Later it down on a towel, next thing I know half of its apart , I took the jets and a diagram printed offline and matched the prices on a towel as they came off, all the keys and everything. Next thing I know it ran perfectly but due to a clogged gas tank I had to do this 5 times in one week. It's so easy even I can do it.

 

Sorry about the delay, but the carb I bought had a bent fast idle rod, which unfortunately I couldnt fix correctly. I replaced it with an rx7 mystery nikki, that I pulled from a 1978 convertible rx7. (You read that right)

The carb i have now runs and drives fine, but this model of nikki is strange as hell, and i cant find any good info on it. Its specific 78 (s1) carb, and it apparently doesnt have a fuel bowl vent solenoid.


I can link some pics here, but yes I will be offering rebuilds and mods on these soon, if I can find a proper way to cost effectively do the venturis and throttle shafts.

 

Pmed !

 

that'll be great! for someone to provide services once more! you sir is a hero

 

Well I have one off of an 82 that is in pieces..if you want it to experiment with send me a pm and we can work something out. It has jets with it but they are too large for the stock carb to handle without a good stripping and probably some major mods ti improve flow...

 

Lol to those reading here who are just interested in the modded nikki's, I finished my first one this week!

Ill have to put hella miles on them like I did the holleys before I can even begin to say theyre "ready", but progress is progress