nikki secondary question
#1
DIRTY RX
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nikki secondary question
I've got an 85 GS with stock nikki 4bl and recently I've had problems with the secondaries not opening most of the time and when they do they also stick open after the throttle is released. Is there a vacum line collapsing perhaps or is it all internal vacum problems? I've worked on a nikki 2bl on my B2000 and it was all internal vacum but I never had a problem like this. Any help would be appreciated.
#3
Old [Sch|F]ool
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My guess is the linkage is sticky. Have a buddy hold the throttle pedal to the floor, hose down both sides of the carb where the throttle shafts are with PB Blaster, and work the linkage manually.
#4
I'm working on this exact same problem right now.
I've noticed something.
When opening the 2ndary venturis with my fingers (manuall, car off) they only open a wee bit. It takes a lot of force (me pushing hard w/ a screwdriver on the levers on the front) to get it to open any further.
Could this be my problem? is it supposed to open freely?
I've noticed something.
When opening the 2ndary venturis with my fingers (manuall, car off) they only open a wee bit. It takes a lot of force (me pushing hard w/ a screwdriver on the levers on the front) to get it to open any further.
Could this be my problem? is it supposed to open freely?
#6
Hunting Skylines
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Originally posted by ioTus
I'm working on this exact same problem right now.
I've noticed something.
When opening the 2ndary venturis with my fingers (manuall, car off) they only open a wee bit. It takes a lot of force (me pushing hard w/ a screwdriver on the levers on the front) to get it to open any further.
Could this be my problem? is it supposed to open freely?
I'm working on this exact same problem right now.
I've noticed something.
When opening the 2ndary venturis with my fingers (manuall, car off) they only open a wee bit. It takes a lot of force (me pushing hard w/ a screwdriver on the levers on the front) to get it to open any further.
Could this be my problem? is it supposed to open freely?
![Wink](https://www.rx7club.com/images/smilies/wink.gif)
Just so you know, if you look down the carby the venturis or chokes are the hour-glass shaped restrictions pressed into the body of the carb.
Last edited by REVHED; 10-09-02 at 12:43 AM.
#7
Old [Sch|F]ool
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Originally posted by ioTus
I've noticed something.
When opening the 2ndary venturis with my fingers (manuall, car off) they only open a wee bit. It takes a lot of force (me pushing hard w/ a screwdriver on the levers on the front) to get it to open any further.
Could this be my problem? is it supposed to open freely?
I've noticed something.
When opening the 2ndary venturis with my fingers (manuall, car off) they only open a wee bit. It takes a lot of force (me pushing hard w/ a screwdriver on the levers on the front) to get it to open any further.
Could this be my problem? is it supposed to open freely?
There are two sets of linkage to the secondaries. One linkage is on the firewall side of the carb, and it prevents the secondaries from opening until the primary is about 50% open, and then it progressively allows more secondary opening, until the primary is at 100% which allows 100% secondary opening.
This is why when you work the secondaries by hand, you MUST have the primaries open fully.
The other linkage is on the radiator side of the carb, connected to the diaphragm assembly, and this is what actually opens the carb. A passage goes to one of the primary venturis. The more air flows through the primaries, the more vacuum is created in the passage, and this vacuum (not manifold vacuum) is what opens the secondaries.
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#12
Adolf Hitler Verfechter
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Ok, all the info have been really helpfull, thanks.
Any idea what could be wrong, when going full throttle it wont go past 5500rpm, like hitting a wall, still runing stock jetting, with big streetport.
had a IDA on, no problems..
Any idea what could be wrong, when going full throttle it wont go past 5500rpm, like hitting a wall, still runing stock jetting, with big streetport.
had a IDA on, no problems..
#14
I'm a bit new to the 12A motors, but on the older 13Bs, there is a little plug with a screw slot in the side of the carb that goes into a vacuum passage that feeds the secondary diaphragm. the plug has a hole drilled through it sideways that the air must pass through. Sometimes, these plugs are screwed in in such a way that the hole through the plug doesn't quite line up with the vacuum passage on either side. Usually, the hole is oriented in a straight line with the screw slot, but not always. For this reason, it is a good idea to remove the plug and confirm the orientation of the hole drilled through it. Sometimes they will not line up when reinstalled, necessitating the use of some sort of sealant so that when you reinstall the plug, it won't move. If the hole is not lined up with the vacuum passages on either side, the secondary diaphrgm won't get as much vacuum as it needs to open fully. Anybody know if this same thing occurs with 12A rotaries? -WG
#16
Dunno if this has been said or not, but on the pass side of the car (carb) you will see a circular metal piece with 4 phillips screws, that is the diaphram and the spring inside. you might wanna chek it to be sure that the diaphram doesnt have a crack/hole etc in it ![Smilie](https://www.rx7club.com/images/smilies/smile.gif)
Lubing the linkage is a good idea, but be sure to hold the throttle open when you try to manually adjust the secondary linkage, it wont move smoothly unless the throttle is like 3/4 or so to the floor.
![Smilie](https://www.rx7club.com/images/smilies/smile.gif)
Lubing the linkage is a good idea, but be sure to hold the throttle open when you try to manually adjust the secondary linkage, it wont move smoothly unless the throttle is like 3/4 or so to the floor.
#18
Old [Sch|F]ool
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A diaphragm problem wouldn't be causeing the secondaries to hang OPEN sometimes.
That could only be caused by sticky/bent linkage, and/or if the small return springs on the secondary throttle shaft are broken.
That could only be caused by sticky/bent linkage, and/or if the small return springs on the secondary throttle shaft are broken.
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Jeff20B
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