I finally got my Nikki apart to rebuild it. I bought the kit from Rockauto like everyone told me. I soaked and cleaned everything but I have 2 huge problems. One is theres a large diaphragm that doesnt come with the kit, where can I find that. The other is I guess someone took this carb apart before because one of the venturis is cracked and the booster ring fell off of it. I know they are removable but are there replacements available? Next problem the secondaries seem to have too much resistance on them. I sprayed them with PB blaster and worked them back and forth but it seems like its still stiff.

Heres a video of the secondaries Opening and closing

http://vid492.photobucket.com/albums/rr290/aprules2/Diamondback/VID_20140901_144052_514_zpstug5rjwn.mp4


Heres a couple pictures of the Venturi The ring fell off after these pictures

http://i492.photobucket.com/albums/rr290/aprules2/Diamondback/IMG_20140901_125637_782_zpshuhvu7tn.jpg


IMG_20140901_125631_972_zpsinimdczy.jpg Photo by aprules2 | Photobucket

IMG_20140901_125627_439_zpsduw0uafr.jpg Photo by aprules2 | Photobucket

Here is the large Diaphragm

http://i492.photobucket.com/albums/rr290/aprules2/Diamondback/IMG_20140901_144430_732_zpsw4ioty29.jpg

http://i492.photobucket.com/albums/r...psqvmes21n.jpg

 

Fix the pic links.

What you call venturis are removable and are not broken from what I can see. They are the primary boosters held in by some jets (can't remeber the name).
Consult the diagram in your rebuild kit and it should show these as distinct parts.

The large diaphragm is from the vacuum secondary. Rebuild kits don't normally
have those included.

 

I know they are removable. I wedged the ring back on to the booster so you guys would know what it is. If you look at it the booster has fractures all over it, and for some reason the ring was broken off. I think someone tried to pry it out once or something. Its the only one like that on the carb. Originally I thought those cracks were rough casting marks then I noticed the ring was busted off. I lifted it out and noticed all the other cracks....

 

Sorry, couldn't see the it as broken in the pics. You will need to source another carb
from a JY and cannibalize it for replacement parts. Or get someone to send you one.

 

Sadly, the vac sec diaphragm for 79 and 80 carbs is NLA. 81 & later is still available some places, but not compatible.

& yep, that booster is supposed to be all one cast piece... and although they they can come out the factory manuals recommend against removing them, probably because they get looser after a few times.

Cant promise anything, but if I get a chance to prowl thru my spares this coming weekend I might be able to help you out some. Not sure what I have squirreled away off hand, but if I have sufficient spares I will let you know.

Are you sure the Vac Sec diaphragm is actually bad, or are you just looking to replace it as part of your rebuild? If you're not sure it's bad, keep it as they are hard to come by!

 

I've taken the booster venturis out before and put them back in. They do tend to get a little bit loose as some others mentioned. I've found that some loctite around the cylindrical insert at the bottom holds them in pretty well if you have reason to remove them. Just make sure everything is clean before you loctite it, and KEEP IT CENTERED UP before the loctite sets in.

As old as these carbs are getting it is almost impossible to rebuild one without needing a core to steal spare parts off of. When I built my sterling nikki copy I think I ended up using 3 carbs to make one. I screwed up several parts trying to figure out what the heck I was doing though....

 

I think my engine is an 81, I just wanted too replace the diaphragm to make sure everything worked properly.

 

If you haven't downloaded the technical reference manuals for the Nikki carb from foxed.ca yet, you'll definitely want them - - great details on the year-to-year differences between the carbs, for one thing.

Foxed.ca - Mazda RX-7 Manuals

 

I printed them and got them bound actually to make things easier. They are very good. Ive never had a carb manual that was so thorough before.

So does anyone know of a vendor who sells internal carb parts. I have to imagine somebody somewhere has one of these thats damaged in some way and could part it out.

 

Most of the spares I've accumulated I got via this forum, in the classifieds section or via discussion here in 1st-Gen. Pretty rare here in Cali to find anything in the junkyards any more.