Hey guys I have noticed that sitting at idle my car misses quite a bit but once its off idle its fine. It has the old Nikki on it which has been messed with I think. I know when it idles down and bounces that it has to do with the idle pump thingy on the back of the carb which I'm not worried about changing cause I know its a pain.

But I would like to get the stumble out of the hitting the gas hard at idle and get the misses out. I have NGK wires and plugs in my cart on rockauto waiting to be bought thinking those might be my problem.

I need to go ahead and put the dellorto on the car and be done with it but I can't afford all the stuff to get it in at the moment (about $250) since I am saving for engagement ring.

Thanks guys
Josh

 

The Nikki is better. Just ask me or t_g_farrel.

Get a rebuild kit from rockauto. Only change the accel pump diaphragm and keep the other parts handy for a full rebuild should you decide to do one later.

Whatever you do, do not touch or change the needles and seats. Changing them always leads to flooding.

Or send the Nikki to someone who knows how to work on them so they run better and with more power than a dellorto.

 

I thought dellorto really opened up the car to breathe. Plus with it I can eliminate most of the vacuum lines that aren't doing anything.

Is the Nikki still better even if I have a full racing beat intake to go with the dellorto??

 

The dell is pretty limited with what you can do with it. Plus they aren't even made anymore. And tuning parts have to come from overseas. The tuning parts can cost as much as or more than the carb.

The only downside to a Nikki is the lack of a decent manifold. The stock 81-85 is not very good but it can be corrected. The 79-80 is somewhat better. The best is the RX-3 type which flows like an RB holley manifold. And then to compare the RB Holley 465 which they set up to work on a 12A, wankel=awesome tested a hogged out Nikki he did himself against his years of experience with Holleys both off the shelf and RB versions, and his hogged out Nikki was a lot better. It had as he described it "insane throttle response" and it ran better with more power than any holley.

As for the vacuum lines, you can get rid of all of them if you so choose. Some people like to keep a PCV system and vacuum advance, which require a couple of vacuum lines.

You can certainly try the dell. t_g_farrel drove one for 20 years but now he likes his hogged out Nikki more. I test drove a dell for a while. It had more get up than a stock Hitachi carb, which has the same venturi size as a stock Nikki. But I missed the secondaries because dells don't have any. Now I can safely say the hogged out Nikkis I drive these days blow the old dell away. They even give larger RB Holley 600 cfm carbs a run for their money, if not tower over them as well.

The Nikki can do a lot for what it is. Kinda like the rotary itself: Small package, amazing performance. I wouldn't want to wreck that with an extinct Italian racing carb.

 

Well that sucks to hear because I paid extra to have the dellorto come with the car and can't afford to have the Nikki hogged out so I'm stuck with what I got I guess.

So how do I fix the stumble at idle and the miss? If I can get those gone the Nikki runs great.

 

Get a rebuild kit from rockauto. Only change the accel pump diaphragm and keep the other parts handy for a full rebuild should you decide to do one later.

Whatever you do, do not touch or change the needles and seats. Changing them always leads to flooding.

As for how much a modded Nikki would cost, it depends on how much work you'd want done to it. But I suspect your intake manifold isn't up to par so it would require attention as well.

 

which rebuild kit should i get from rock auto??

the airtex or the standard motor products

 

Stay away from airtex! They use fiber washers! Those are terrible!

Standard looks like hygrade so that's the one to get. It should come with aluminum crush washers like hygrade because that's what I see in the picture.

 

ok and how hard are these to rebuild? there looks to be alot of parts involved.

 

Well since you aren't going to keep any emissions, the only difficult part is literally the disassembly. Which isn't all that hard. you just need to have a few basic tools like an impact screwdriver because it makes your life easier while removing screws that haven't moved in 30 years.

I use the impact screwdriver in these places:
The choke pull-off on the air horn is a very short screw that always sucks to remove.
The two screws at the vertical section where the complicated choke bracket attaches to the throttle cable bracket.
The return spring bracket on the air horn.
The three phillips screws on the altitude compensator.

Oh I just remembered there is a pdf made by vipernicus Jon that gives some pretty accurate info about how/what to do. I do it a little differently with better results but his info is for more general consumption and easier to digest. So check this out. http://foxed.ca/rx-7/Carb%20Stripping%20Draft%201.pdf

Note you probably don't have to throw away or break/damage as much as he does. I, on the other hand, tend to mod all my carbs with boost in mind so my procedure is going to be a little different. Anyway, enjoy!

 

Thanks for the help man but the car was totaled this morning on my drive to work. I'll post a thread later