dahammer20

Just bought a 82 Mazda rx7. I'm gonna be restoring and modding the rotary engine. I have a problem with the carburetor. It'll crank right up and idle for a little bit then die. was wondering if it would be cheaper to replace the factory carb with a performance carb or buy a rebuild kit and rebuild the factory. which one is cheap and easier. and if I replace the carb with a performance one what will fit. its the 12a rotary

misterstyx69

iTrader: (142)

You should address why it is starting and dying and not just assume that by changing the carb that things will be all warm and fuzzy.
This sounds fuel related and by that,the whole fuel system needs to be cleaned.Start at the tank(pump,screen,etc) and end at the carb..

dahammer20

It hasn't been ran or driven in over 5yrs. When you start it before my mechanic played with the carb you had to play with the choke or it would die and there was a bad burning gas smell. after he played with it you don't need to play with the choke as much bit if you don't keep your. foot on the gas it will die but no burning gas smell. the main problem I see is that there's no telling how many unattached, capped and missing vacum hoses. would replacing all those hoses remedy my problem with the idle? The whole car is stock.

misterstyx69

iTrader: (142)

and that my friend is why,.
First clean the whole fuel system.

Myself?..I would not keep on driving it and complicate it more by shoving crud further down the fuel system.
Clean 'er up ..and get some info on your Car in the Series Specific section so you can address the vacuum hoses or whatever may be going on at the engine.
I'd be happy to help you but I am a S4 Engine guy and then again I modded the **** out of my engine,so much that I gotta get someone to tune it for me..lol.

diabolical1

iTrader: (3)

welcome to the board.

agreed. restore/refurbish the fuel system. whether or not you choose to restore the rat's nest is up to you, but you should start with a good cleaning of the Nikki or a rebuild. the tank should probably be cleaned as well. at the very least, clean the lines all the way through because it makes no sense getting the Nikki done if there may be debris coming through to clog it up again. bottomline is you and your mechanic have some things to discuss.

dahammer20

I'm going to be replacing the carb for a little more hp longer down the line anyway. would it be good to replace it now and put a performance one on? And what will fit the factory manifold?

erick31876

iTrader: (8)

first off welcome to the Board, second clean that Fuel system,your gas tank should have a drain plug on it you can drain the fuel out from there then flush out the lines.if you still want to upgrade the Carb,I would go with a racing Beat Holley set up,they are already set up for a rotary engine and are easy to tune

dahammer20

Is there a cheap performance carb that will fit the stock manifold? I look led at that set up and its out of my price range.

Evil Aviator

Since you mentioned racing, I would not recommend buying an aftermarket carb until you read your racing rules to see what is allowed for each class. In most cases, aftermarket carbs will bump you up into a much higher class where you will get your butt kicked by people with $50,000 cars. The stock carb will keep you down in the lowest racing class where people with $3,000 cars will kick your butt because they are excellent drivers, but at least you have a fighting chance once you gain some skill.

Your best bet is to have a professional rebuild and tune your current carb. The cost will probably be about $200-300. This skill takes a lot of experience to master, so you can't do it very well by yourself. If you don't have the money, then get a part-time job to pay for it, or work overtime. On several occasions I have worked overtime to pay for professional automotive work that required skills or expensive tools that I lack.

No.

Nothing any good. The popular performance carbs require a matching performance intake manifold. Here is a list of common performance carbs and how to match them to your engine and porting:
http://www.racingbeat.com/manuals/intakeguide.pdf

Cookboy

iTrader: (10)

Drop tank. Clean tank and fuel pickup. Put a new filter sock on fuel pickup. Replace lines to and from tank.
Read all you can about nikki rebuilding and modifying. Read all you can about the rats nest, its removal, and what needs to be altered/capped for proper timing advance and crankcase ventilation in its absence.
By now it should be apparent that the Nikki carb is the best intake for a stock 12a.
Buy a rebuild kit for your Nikki. Rebuild it.
Drive the car and delight in the work you did.
Buy another Nikki and modify it as far as your skills will allow.
This is the path to 12a happiness.

diabolical1

iTrader: (3)

i think we should take a step back here for a minute as we seem to be getting a little horse-before-cart. who's going to be doing the work with this? you or your mechanic? and i mean no offense, but you don't sound proficient enough yet, so the question is is your mechanic proficient with these cars/engines?

if you want a performance carburetor, that's fine. i won't try to talk you out of it, but if we can agree that even a "performance" carbie will require some time and money beyond purchase, then you can see why it makes sense to simply get the car running well with what you have first. a rebuild kit costs, maybe $60 and even if you have to pay someone else to do the rebuild and initial setup it will be far less than adding the cost of a whole new setup to the mix and have to do all of that (minus the rebuilding) anyway.

work with what you have. get a feel for the car/engine, then if you want to move on to aftermarket stuff, then have at it.

also, as Cookboy alluded, a well-built Nikki can rival aftermarket carbies - especially on stock ports. just FYI ...


simple answer is NO. many moons ago you could find adapter plates to use a Holley, but i don't think they exist any more and i wouldn't recommend holding your breath for one to just pop up on craigslist or ebay.

from RB, yes, they are. however, i have to comment on your "easy to tune" comment because - especially in this subforum - comments like that can potentially get someone up THAT creek without a paddle. i think i know my way around a rotary after all these years and i have successfully tuned a Holley once, and it was anything but easy.

let's not get into the fact that someone will always point out that you can buy one used ... or ... get them cheaper from Summit or Jegs and oh yeah, the RB mods are not THAT hard, and you can have great Holley system for a fraction of RB's price. i now people have been successful at doing just that, but they are the exception, not the rule.

i'm not picking on you. however, just try to be mindful of your environment (New Members) and phrasing that may be misleading.