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Now that I am running again after stripping my Niki, I am trying to understand if I need to keep the solenoids shown in the picture attached. Seems like they are never powered so just wondering if they can be removed and plugged or is there more going on inside?
One is a richer solenoid that only functions at idle when conditions are met. The other is a power valve that only functions at a higher RPM while driving. I think it richens up the mixture to keep the thermal reactor fire "lit" inside. It is akin to the semi-firing trailing on the 1980 model.
Both serve no purpose on a stripped Nikki.
I keep the richer solenoid (located between the secondary barrels) and just snip the wire(s). Yours looks like it probably leaked and was RTVed up. Or maybe the wire insulation was cracked. Snip time. As for the power valve located down on the baseplate. I've removed it and filled that hole in with quicksteel in my 1980 carb. Seemed to work fine. I also eliminated the other parts of its circuit inside the carb. I kept the strange brass fitting inside the main body down at the bottom of the float bowl, but I wrapped it around with teflon tape and deleted the long spring loaded rod extending down to it from the air horn. Just hacked it off and lightly hammered the nub over so it would not sit in there loose and rattle around.
Thanks for you input. If fact this is on my 1980 rx7 which I have replaced the thermo reactor with a stock cast iron manifold from a later model I think it was from a 1981 rx with a cat. So I will follow you suggestion ( and yes the rtv was to repair the wire ). When the power valve was removed did anything change in the performance of the engine as far as you could tell?
The factory jetting of these 1980 carbs would have been changed by probably 1 number as a result of whether they had those solenoids or didn't. The end result was either a 94 or a more common 93 for the primary fuel jet. The number represents aprox .94mm or .93mm. In practice the difference of + or - one one hundredth of a millimeter really doesn't matter worth a hill of beans, but the factory liked that kind of resolution. I like to work with about 2 numbers when I can because I like that level of resolution, but I really don't think you will need to worry about it on your internally stock factory carb. Just do a half turn counterclockwise of your mixture screw if you need to, to slightly richen it up at idle. That is it. Couldn't be simpler.
Thanks for your help,I got something to do this weekend. Did you happen to install an aftermarket PCV on your car after stripping up the carb? If so what did you use ?
On one I used a Fram FV333 and on others an FV266. On another I used the stock purge valve but I probably did not do it right because I didn't know what I was doing back then and had not studied the phenolic spacer. These days I know the middle nipple on the FB spacer communicated to both primary runners and is a great way to hook up a PCV valve or anything else that you want to pull a vacuum from both runners.
On an SA setup like yours, I'd use the altitude compensator located on the intake manifold. I'd hook this up to the oil fill nipple using a 5/16" hose. It didn't cause too big of a vacuum leak-like symptom at idle. In fact it seemed to do on on my Hitachi 13B setups. I have yet to try this option on a Nikki setup but I imagine it would be pretty similar to suck out moisture.
On other setups, I drilled a hole in the oil fill cap and leave both nipples open to breath with a short length of hose on them.
06-30-20, 10:55 AM
Niki Carb question?
Thanks for you input. If fact this is on my 1980 rx7 which I have replaced the thermo reactor with a stock cast iron manifold from a later model I think it was from a 1981 rx with a cat. So I will follow you suggestion ( and yes the rtv was to repair the wire ). When the power valve was removed did anything change in the performance of the engine as far as you could tell?
