DannDZ

And @madkaw, well I messed with 17! Not in defiance, but because I did it before I saw your reply. The jet has now fallen further in (15) Jet Bearing.(See picture) Am I beyond saving? Is there a way for me to raise it? I'm not asking for step-by-step instructions, just point me in the right direction. I have a copy of Tuning S.U. Carburetors, 2nd Edition in hand. Are there specific YouTube videos that might help me fix my problem? Thanks.

I hope your advice is not too late! I've given it a few partial turn. I'll get it "re-set" and hope for the best. Thanks for the other tips. I'm getting a strong vibe that once you get it running, the rest is a fine art of balancing the variables. And that exactly what you need to do to get it in tune is different for each "instrument." (As an IT guy for years, I am really fascinated with the difference between "getting the bugs out" of an analog system, like the Z, and a digital system as found in any code. A great experience.)

@duffman @Mark Maras @240260280 I followed your suggestions, busted out the trusty endoscope and took a look. There was nothing different about the parts in the two "stacks." Neither spring has any spring left in it. They both just stay stuck at the top. But I don't think that's the problem. What I think I need to do is move part (15) Jet Bearing up into the body further and then lock it in place using (17) Jet Locking nut. At least that's my theory. When looking at the to (17) Jet Locking Nuts, it does appear that the one on the carb with the problem is not seated as firmly against the carb body as the other one. I'd like to turn it tighter, but am a little concerned about trying too hard. Any further suggestions? Does this diagram help?

I will review both of these possible solutions. Thanks for your input.

I don't think bending is the right action. I can check some diagrams, but I don't see how that will move the jet up. I need to be able to raise the jet with the Jet Adjusting Nut, but I have run out of turn to adjust it. So it seems to me that I need to move "the whole assembly" up a bit so that I can have some more room for adjustment.

I am in the process of tuning the round-top SUs on my 71. The first step is to set the idle screw and and jet level. The jet is supposed to be even with the "bridge," the flat part where the piston comes to rest when it is "at rest." This is possible on one of the carbs, but I cannot raise the second jet high enough. It is about a 16th-of-an-inch below being the bridge, I cannot get it to a flush position. Is it possible to loosen the jet jet locking nut and then make a "gross" adjustment so that I will be able to set the jet to flush using the jet adjusting nut? An other way of putting is, if I was rebuilding my carb how would I know where to place the jet before I held it in place with the Jet Locking Nut before I reassembled it and then made adjustments with the Jet Adjusting Nut? In case it helps, here is an image from the web showing the jet in the bridge. Can't tell from this angle if it is flush or not, but this is what I am trying to adjust.

Very close, I live in the Center Grove area. Thanks for your advice and the table. It will certainly be helpful when I try to figure out what is going on. I may not be as far off as I suspect. What I really don't understand is why this is so far from the "factory specs" in all the manuals. Regards, Dann

How can you tell the timing under all these different conditions? While cranking and idling I can understand, but how can it be measured at cruise? And, can you provide any insight on why everyone suggests that is may be OK when it is so far from what the manual says? Is it just the nature of a warn system that you adjust until it runs right, the book be damned?

I don't here any pings on load, but I can listen more carefully. When warm, haven't tried it cold yet, it starts with no choke and no foot on the accelerator. If I didn't know the timing was off, I'd think everything is fine.

So many great suggestions! Thanks to everyone. I have much to learn. Today I am going to (try to) tune and balance my carbs. Then it is back to setting the ignition timing. Having not actively worked on it for about 20 years, I'd forgotten how interrelated everything is. An how ANALOG! Cars today make all those interdependent adjustments on their own. Thanks again!

I am attempting to tune my '71 with the old round top SUs. I performed a rudimentary (at best) carb tuning and then turned to the ignition. While tuning the engine I was able to get the it to idle well at 800 RPM and it had strong acceleration up to about 6K RPM and 90 MPH. (On a track only, of course! ?) But when I look at the ignition timing with a timing light, it shows that it is about 25-degrees BTDC! The distributor is at its limit of adjustment. Is it possible/recommended that I remove the distributor itself and move it by "one position" to fix the problem and get me back to the right range where I can make timing adjustments just loosening the distributor cap and adjusting? What is going on and how I can fix it? Thanks!

Thanks AZ-240z. Very helpful.

I refreshed my 8/70 240 20 years ago. For some reason I did not replace all the jute padding. But, I did safely store it all these years. Now my challenge is determining where everything goes. I think the two pieces on the left and right are under the passenger's feet. The other three in the middle, I really don't know where to begin. Finally, there is piece of black cardboard with some "insulation" on the back. Does that belong on the driver's side? Thanks

Thanks for the suggestion. It's something to try.

Thanks again. I did look at the links, but after I responded. Yes, that is a good source of information. Someone mentioned a replacement for the upper rubber "bushing." I took notes and will do some more searching. But in most cases it seems that this is just the nature of the transmission and that there is not much that can be done. I do wish I could remember how it shifted back when I bought it in 1975 with 25,000 miles on the odometer!

Thanks. Based on my research that makes it a Type A, aka "the one with the goofy shift linkage, AKA "monkey-motion" shifter." That is logical and confirmed. Now, can anyone tell me how I can make it so I don't have to search for the next gear? I'd like it to have some feel!

I am attempting to tighten the shift linkage on my early '71. I had some new nylon bushings in "stock" so I thought I'd use those. When I got to the linkage, there was no match with the bushings. So, I think I have a Type A transmission. Can someone tell from the picture below? Also, how do I fix this linkage so I don't have to stir to find the gear? Just a different bushing? Thanks

Hi neighbor! I'd down in the Greenwood area south of Indy. I'm just trying to attend to some details on my car. So, what I understand from you is that earlier cars had silver decals and sometime 5/71 or earlier they moved to the gold decal. So, my 9/70 is likely to have a silver 1971 emissions sticker. Off topic a bit, but do you happen to know anyone in the area who is good at setting up the original round-top carbs. I'd like to get them tuned properly and I really can't be too sure of my talent!

Thanks for your input. The decal you shows matches the reproduction I bought, and still have not installed, from Banzai in 2001. My air filter box "the earlier one without the snorkel butterfly and no riser tube." I understand that "back then" dealers had some flexibility in what year to title a car. It depended on a number of factors including manufacture date and when it arrived in the U.S. As I said, mine has a manufacture date of 8/70. Unfortunately for me now, the dealer decided to title it as a 1971. I understand why, but I do wish it was a '70. I think the biggest question for me right now is were both '70 and '71 emission stickers silver? If they were, then I more than likely have the right one "in stock." If '70 had a gold-tone, then I need to find a gold-tone sticker. May be time to call Banzai!

Thanks jfa and 240dkw. My air filter box stickers match DE-03. I only have two stickers. You are right about my air filter box "the earlier one without the snorkel butterfly and no riser tube." My primary interest is in the correct "Vehicle Emissions Control Information" sticker on the hood. I bought one in 1998 from Bonzai and I think it was gold-toned. At least that's what it looks like now. My brother hit it with a power washer before a show and the printing is gone. In 2001 I purchased DE-12, the '71 Tune-up/emissions decal, to replace the washed off one. It has not yet been installed and it clearly says 1971. So it comes down to two basic questions: 1) Do I need Bonzai's DE-07 or DE-12? 2) What color are/were they? Gold-tone or silver? Thanks for all your helpful comments.

Can someone tell me what is the correct emissions under-hood decal for a Z registered as a '71 and a manufacture date of 8/70? Is it the silver/white as for the 1970 model (https://www.zzxdatsun.com/catDecals.php) or a gold-tone one with a '71 date mentioned? There is no emission equipment on this car. It does not have the "new" air cleaner box. Were these applied at manufacturing or in the U.S.? Where did the sticker change? Any insights are appreciated.

Thanks for the idea. I'll look at my books a bit closer. Any ideas on how to conduct a "deep search?"

I've owned an early '71 (8/70, 8325) since 1975. I've moved since the purchase, so the title does not show the original owner. The serial number VIN does't work in today's VIN checkers. I've attempted to contact the selling dealer, with no luck. (I understand that it was the first Z that they sold.) Since I was 19 at the time, I didn't keep my sales receipt from when I bought it from the first owner. I'm open to all suggestions on where to go from here. What have you done to document the history of your car? DannDZ

I saw OEM blades offered on Ebay for $200 within the last few days. Too rich for me, but get them while you can.

sfm6s524, which blade did you get from ZDepot, the top one or the installed blade?