Nikki Carb question
 

Hello everyone, this is my first post so please be patient with me. I have a 1980 rx7, and the guy i bought it from said it had a different carb than the original , but he gave me the original with the car. Anyways, I bought a rebuild kit and been studying alot of articles on this awsome site for a few months already including all of sterlings, rx7 carl, tuturials,plus i downloaded all the manuals i need an all info on the 1st gen faQ page. All you guys are great, and I will try not to make this an eye-sore, so on the next paragraph I will ask my question.

Ok , here we go, here we go!! I removed the carb from the car( which the car ran but like crap) and i noticed it was different from the original. from the manual I dowloaded it shows that the carb that was on the car when I bought it was a 84' nikki carb, it had that high altitude compesater ect that the original dont. on the airhorn of the carb I noticed the primary opening was alot smaller than the origianal 80' carb. I wanted to rebuild the 80' carb and use it but the float bowls have some serious rust , even after dipping in carb cleaner dip, and scrubbing. I plan on removing all emissions plus stripping it down ect, the question is, Can I use the airhorn from the 80' carb on the 84' carb. can I use the best, cleanest, rust free parts from both carbs to make one carb with the rebuild kit.

Contrary to popular belief the 79-80 carbs don't flow more despite the appearance.

I'd just rebuild the 84 on its own and go with that.

Jon

Interesting and well thought out question. Thanks for doing your research. Off hand, I don't have an answer, though I'm sure Sterling or RX7Carl will. Since you're stripping emission, my guess is that it won't make any diference which air horn or float set you use. Best advice I can give is try it out and see if the parts interchange.

In the carb manual, there is a chart for jet sizes for the various years, use the ones that fit the main body and match the engine year. Let us know how it works out for you.

Wow!! thanks, It is awsome getting a reply. I will rebuild to the best of my ability. It just seems that the bigger opening on the 80' airhorn will let in more air. Oh well , If it dont work out for me I can always send it to Sterling or even to Rotary Shack for a racing prepped rebuild, but I want to try it anyways. Once again thanks!!!

Yeah I remember seeing in one of Sterling's threads that the 79-80 airhorn doesn't flow more air, and the 79-80 carbs take so much more work to bring up to "Sterling" spec that it's not even worth it. So he only uses 81+ carbs.

So if your 84 is in good condition, use all its parts.

If you decide to interchange parts be prepared to troubleshoot, and make sure to swap entire assemblies. IE: if you're going to swap the floats, swap both sets with their needles and seats. If you mix-and-match you'll end up with problems for sure.

Jon

thanks again, Now I will just rebuild the 84' carb and consider the disassembly of the 80' carb as "practice" to understanding the rebuild process. thanks once again. my next post will probably be about making the extension arm on the acceleration pump which will be modded to provide that extra sqirt of feul for the mech secondaries, which I read on sterlings post but cant quite visualize. :uhh:

Rebuild it stock first, so that you can get it working and understand the process. THEN get into modding.

Jon

Before I had much experience at rebuilding the Nikkis or found the online carb manual, I always kept 1 carb stock and untouched for reference. At first, I dismiissed the Nikkis as being overly complicated and went straight to the aftermarket 2 barrels. I've since found the Nikkis aren't as intimidating as first thought and do have performance benifits.

A stripped down Nikki is an entirely different carb to work with than one in it's oem configuration. The online carb manual does a decent job of explaining the workings of the Nikki, much better than most of the other carb manuals I've found.

Thank you for your input, it is appreciated,I just dont want to go through the experiecnce of rebuilding the carb and then I cant even start the car!! but then again if I do it successfully it sure will be gratifying.:icon_tup:

If your engine has the 79 style intake manifold, use that. It's the prefered intake mani for max flow. It will fit with the later style carbs but there is a difference in the recirculating exhaust port between the 79/80 engines that are equipped with the thermal reactor exhaust system and the FBs that have the catalytic exhaust system. If you have an 81 or later engine block, you will have an exhaust leak at the rectangular port in the center iron. Post a pic of the intake/exhaust side of the engine once you have the intake removed, along with the carbs and intakes you have.

Thank you, yes my car has the 79-80 intake the 12a is also the original. You see when I bought the car the owner told me that everything is original but the carb. The car was sitting for a few years, so I replaced the fuel filter, plugs wires, cap and roter, cleaned the fuel system(quicki-poured some fresh gas with some b-12 chemtool and disconnected the fuel hoses and filled a container till clean fuel came out then put new filter) ect. turned the key and pulled the choke and it started right up. no power whatsoever. took it on the highway and on 4th -5th gear at 3500-4000 rpms was barely going 55mph. did research( should of tried the atf treatment) but that was six months ago when I didnt know anything about rex,s. so I decided to rebuild my carb, get rid of the rats nest per maxdatrix pratch tutorial, get headers, ect. ( which I will start on the carb tomorrow)

Anyways, before I become an eyesore, I plan on getting a welded up intake from rotaryshack, Im slowly but surely getting the overall Idea about what I want to achieve , yet I still have alot to learn and alot of questions which Im going to post one right about now. Thank you and I will post pics soon, appreciate you, and others that contribute.