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I brought a Weber 48 DCOE for my 1985 GSL RX7. I thought it was a complete conversion kit from NikkI to Weber and it's not. The NIKKI was done. I live in Southern Maryland and I don't know anyone here who knows how to work on 1st GEN Mazdas. After much frustration, I went out to get a carburetor that works. I have remove the NIKKI and some of the nest. I need help with how to setup the Weber linkage and other stuff I haven't consider. I have cable linkage there from the NIKKI and the choke cable as well. Please HELP!
First do some searches on here, its all been covered before. You sure its a Weber and not a Dellorto? I thought webers in DCOE only came as 45mm. Mikuni/Dellorto/Weber all setup about the same. Post some pics here to show what you have as well.
Looks brand new, where did you get it from?
Like mentioned above, try some searches to see what has been discussed already.
Good luck and keep us updated on the progress!
I have stockport 12A and I went to a 45 DCOE with nearly the same intake manifold.
I simplifies a lot the motor bay, but you ABSOLUTELY need a wideband to set the carb correctly. I installed a AEM uego, the sensor has been welded on the Racing beat manifold where the two pipes join together, but if you can, do one plug per pipe so you can check how each rotor is behaving.
I clearly gained power (ignition is stock, only exhaust is full racing beat, the street one, not the race one), but below 3000rpm I still need to tweak the thing as it struggles if I just hammer the throttle.
Fuel consumption went through the roof, but that is also because my driving has changed (love the noise of the Weber, and I have only done mountain climbs and canyons lately).
At the moment I have (45 DCOE):
-38mm chokes (with 36mm, power was decreasing from 6000rpm)
-F11 E-tube (want to try an F16 to see if it helps with low rpm transition)
-65F9 idle jet (slightly too big, 55F9 too small, I need to try in between)
-55 pump jet
-170 main jet
-190 air corrector.
As I said, I am not happy with low rpm behaviour, so I need to work on it when confinement is over.
It is written everywhere the starter circuit is useless, that is is easy to start. It is true in summer, but not in winter, and I wired the starter again this winter, it hels a lot.
Last remark, I have a Malpassi King fuel pressure regulator set at 0.3barg (4.5PSI) and the stockfuel pump (which is so far OK, but I have a Facet Gold in stock just in case).
if you google it there is a chart of E tubes vs engine size, and the F11 is basically not applicable to a rotary engine. they should be removed and thrown away with great enthusiasm.
i never did a back to back with mine, but i'm running an F8 (its what Mazda wants in a 12A with a Weber).
Mivroum, Can you show me you DCOE Niffi throttle cable mods? I ordered the Weber 48 DCOE carb conversion kit from AMAZON. My NIKKI frustrated me so badly I just gave up on it. I totally removed the NEST and don't know what to do with all the empty vacuum nipples left. Thank you all for your guidance and input.
The Nikki can be frustrating, but getting an aftermarket carb to have good drivability can be just as frustrating.
The nikki is frustrating because all the extra crap on it can cause problems,
Aftermarket is frustrating because it has to be tuned.
not too bad if you know how, but frustrating if you have to learn from square one. And to do it right you really have to start with how and why carburetors work, Every engine and set up is different so recommendations from others may not work for you.
At least with the Nikki you know the jetting is right and all you have to do is make sure it is rebuilt properly and that all the extra crap is functioning in a way that wont cause problems. Its all covered in the FSM, available free here and online.
If you are frustrated with something simple as a linkage then you may be better off with a nikki. I know you've been there and done that but Im telling you that your future with the weber knock off will be no piece of cake. I speak from experience, I did the same thing you have done, same manifold, different brand ( Mikuni) , and only after years of learning carb theory and how to go through the tuning steps did I get It to run really well, and then only after modifying the accelerator pump. I moved on to twin downdraft webers and along with the wideband O2 guage really learned about tuning. They are on a highly modified 1st gen of mine and they run great, but I have spent more money on jets and tuning parts than I did on the carbs.Since then I have obtained several stock 1st gens and have learned more about the Nikkis. You can make the Nikki work without learning so much about tuning. Its just a matter of getting all the parts in the right place and getting a few simple adjustments made, again all covered in the manual. This is especially true on a stock motor.
This forum is full of threads of people trying to get aftermarket carbs right and most never get it as spot on as the nikki will be if you can just get it put together right.
The picture is bad, and it is only v0.1, but the idea is to reuse the original cable, on a custom braket that bolts on the carb screws, and on a lever on the throttle axle of the carb.
Wow! Thank you. I will get on that for mine. Thank You Thank You. Did you delete you air pump? A close picture of your linkage solution would be great.
I will make a better picture end of this week, working on a improved linkage now.
Yes, I removed the thermal reactor and the air pump, and I went with a twin belt pulley on the alternator to avoid slipage.
Mivroum I'm working on buttoning up the vacuum fittings you show me on the intake. Thank you. As Tommyeflight89 mention the carb is not a Weber. It's a Chinese FAJS 48 DCOE and yes I didn't know.
if you get that setup running I'm super curious to see how it goes. I have been looking at getting a weber setup going on my 12a, since I have a holley setup that I don't really like. I have heard very mixed results with those knockoff webers so I am very curious to see if you can get yours up and running good.
For the vacuum, you may delete the small hoses to the vacuum advance if you set the timings with some advance with a proper light (I do not have the light, it is still stock timing which is not optimal).
You only need to connect the brake booster, nothing else.
All the other vacuum stuff from the Nikki can disappear.
I am cleaning my throttle adapter, it is a bit of a DIY parts and will look better once the welding have been sanded and the part repainted.
sounds good I'm looking forward to seeing someone go this route before I go for it myself. did you get the manifold and carb off Ebay? they look similar to the ones I've seen on there
I brought mine from Amazon. They presented it as a conversion kit for 12A's Nikki to Weber. However, It is a Chinese FAJS 48 DCOE and I'm anxious to see how it performs. I went back and read the Amazon description of 12A's Nikki conversion kit and it never said it was a Weber or that it was FAJS. Slick!
03-27-20, 09:38 PM
