Carter afb rebuild

[arnulfo de l.a.]

I finally started the rebuild of my primary carburetor on my 65 gs. Back in 08' I posted about the rough idling I was having. Well I have the carb apart now and soaking as I post this. Boy was there a lot of crud inside. I looked for the corrosion that is supposed to be common on the bottom and found none. What I did find,which I mentioned in my 08 post, is a lot of slop in the throttle shaft. The car would require a quick snap of the gas peddle to bring it down to it's set idle. I'm thinking this slop in the throttle shaft is the cause.I've got this kit with bushings and a drill bit that is made to repair this condition. I don't want to ruin this carb .I believe It's original to the car. Has anyone ever used one of these throttle shaft repair kits? I also have a couple of 60's harleys that I wrench on myself . They both have original linkerts carburetors that sometime get sloppy in the throttle shaft area and cause a lean air/fuel mixture. The fix for this problem in linkerts is the installation of Bushings in the carb body where the throttle shaft passes through.this process tightens the fit and cures the problem giving the bike a nice steady ,smooth idle. I know that linkerts and Carter are 2 different beasts but I do believe that they both use the same basic principles.

So what say you men on this great forum? Should I go ahead and try to fix the slop in the throttle shaft or leave it alone? Am I on the right track here?all help and advise much appreciated.

Arnulfo

[RivNut]

I don't know that I'd try to do it myself, but I definitely think that it is something you should have addressed.

Are there any instructions for making sure that when you drill out the carb body, that you keep the hole centered? If there were some kind of fool proof guide for doing that, I might be tempted to do it myself.

Ed

[arnulfo de l.a.]

Ed

There are instructions and it seems pretty straight foward . The kit is ZAKO-ATS KIT -ZA-01. What supposedly makes it foolproof for drilling is the specially made reamer

Arnulfo

[JZRIV]

For the best performance, you must have the throttle shafts bushed otherwise you will likely chase carb inconsistencies forever. While its not rocket science, its best to have this done by a competant shop who has experience doing them. Not familiar with the kit you mentioned. Can you post a website link? As long as the shaft holes are held precisely on center you'll be OK.

Edited June 17, 2013 by JZRIV (see edit history)

[RivNut]

I'd be afraid that if the hole for the shaft was even the slightest bit eccentric, I'd do the reaming off center. Unless there's a special jig that attaches to the carb and centers the reamer, I'm with Jason on having it done professionally. But do have it done; sounds like it could be a big part of your problem.

Ed

[arnulfo de l.a.]

I hear what you men are saying. After im done cleaning everything up, im going to look at everything a little closer and then decide whether to take it to a pro or not.

Jz, if you google ZAKO ATS it comes right up.

Thanks men,

Arnulfo

[60FlatTop]

Or take a long piece of cotton string and wrap the shafts where they exit the base of the carb. See if it makes a difference. That's step one. Step two would be to test it for the next 20 years. If it works out OK then you can disassemble, bush it, and make the permanent repair. Or extend the test just to be sure.

Bernie

[carbking]

Before deciding to install bushings, I would suggest:

(A) use a dial indicator to determine actual clearance

( determine the "design tolerance" for the Carter AFB, and compare that to actual

You might be surprised.

Jon.

[arnulfo de l.a.]

Ok Jon that makes sense. How do I determine design tolerance for the shaft clearance? I thought that was determined by the designers. I tried looking for throttle shaft clearance specs but found nothing. Do you know what that spec might be?

Thanks ,

arnulfo

[JZRIV]

I always thought .010 is typical max but I honestly don't know the AFB spec. Maybe Jon will confirm. Great suggestion and question.

.010 is only .005 per side and that isn't much at all so you can probably get away with a bit more than that in reality depending how particular you want to be. If you grab the shaft and can easily see, feel and hear movement they probably need bushed.

I looked at the Zako ATS kit and it looks quite interesting. Never heard of it before. I'd like to get a report from someone who used one because at $217 I'd want to make sure it does what it says. It seems too simple to be true. The process may assume the hole is worn evenly around the circumference??? You would want to check for wear on the shaft itself also.

Edited June 18, 2013 by JZRIV (see edit history)

[carbking]

The Carter AFB/AVS were 0.016~-0.022

Jon.

[carbking]

I just took a look at the blurb on the "kit".

Before commenting, let it be known that we are no longer doing ANY work to carburetors. Our focus now is on kits only. Thus the following is a professional opinion, and NOT an attempt to advertise for work.

Now comments:

The tool is advertised as "foolproof", but with no warranty???

The tool is advertised as being used with a hand-held variable-speed drill??? I have been rebuilding carburetors since 1959, and would never have attempted to bush a throttle body using a hand-held drill. A vertical mill is preferred; or at least a really good quality drill press. One might price another throttle body before the hand-held drill ruined the one on ones carburetor.

And one tool works on all of these various carburetors??? Design tolerances vary from make to make; what specification is being used?

I didn't see the price of the tool, but there are professional shops that will do this work in the $35.~$50. range, and finish the job to the tolerance you specify.

Again, we no longer do this work, do NOT send throttle bodies to us to be bushed.

Somewhat off-topic, but not completely: a good lathe and a good milling machine are two of the most necessary tools for ANY hobbyist. Lots of shops with older American-made tools having auctions; and with the current price of the entry-level off-shore tools, many ignore the bargains that are available. Personally, I would much prefer the quality of some of these 50 year old precision tools to the off-shore stuff currently available. While I use a Sherline for much of the precision carburetor parts, we have a 60 year old Craftsman 12 inch industrial lathe that we use for heavy jobs. I paid $400. for it with a bad reversing switch.

Jon.

Edited June 18, 2013 by carbking (see edit history)

[60FlatTop]

My wife is working at the library tonight so I am home alone looking at car websites when I should be surfing around for much naughtier stuff. I do get some entertainment, though. I'm just sitting here thinking about many of the threads on the forum and how they might relate to even subtleties is this thread.

I know the CarbKing and I have dial indicators.

I am also getting real entertainment connecting two thoughts. "I have been rebuilding carburetors since 1959" and "let it be known that we are no longer doing ANY work to carburetors". What a collection of stories must have led that decission.

I'm picturing a girl, a scarecrow, a tin man , and a loin saying "We've come so far to have you fix our carburetor and make our Buick run good again...."

What, no magic!

Bernie

[lrlforfun]

OK Riviera People: While I do not have 3% of the carb experience Jon has I can ask this. Is the rough idle been actually isolated to the carb? There are so many other variables. True, the wear in the throttle shaft can cause a vacuum leak causing rough idle. Again, has it properly been diagnosed? Remember, Jon is in MO and the car is not there for him to diagnose. Mitch

[arnulfo de l.a.]

got the carbs rebuilt and installed. it made a HUGE difference in the cars performance! the car would hesitate on a turn, crap out while parking , hesitate when accelerating and hard starting in the morning and when hot. all those issues have been corrected. she starts in a flash when hot and cold and does not hesitate under any circumstances.im still having issues with the throttle plates and or linkage not allowing the throttle plates to close completely without giving the gas peddal a quick snap. after reading the opinions of the men that posted about using the bushing kit , i decided not to do it. i do not want to chance ruining these carbs . they are original to the car and upon closer inspection i saw that the excess slop in the throttle shaft is side to side which would not be corrected with the bushing installed. i know there needs to be some side play to keep the linkage from binding but how much is too much? i also had a hard time geitting the idle below 700rpm ( even after snapping the gas pedal to make sure i got the proper throttle plate closure) without turning the center big brass air adjuter all the way in. i got some brake cleaner and sprayed around both carb bases , around both intake manifold to head gaskets, sealed off ALL vacuum ports in carb and intake manifold and got no change in idle speed when i did the spraying. if i recall correctly i think i read somewhere on this forum that there is a plug on the underside of the intake manifold that goes bad. if someone can please tell me if my recollection is right or wrong i would greatly appreciate it.

the other issue im having is pinging when i accelerate while doing highway speed. if i ease into the gas peddle ,no pinging. but if i step on it like say to pass a car it pings real bad. im thinking too much advance and i suspect the reason is because i may not have the rubbber or brass counterweight stops that limit the advance under these circumstances. can someone please tell where these stops are located in the distributor and where i can buy them? a picture would be ideal if anyone has one.

all in all im having a good time tinkering on this ol classic. its a great example of how our great country built things to last back then. im determined to correct the throttle plate and timing issue. now that im semi-retired i enjoy nothing more than wrenching on my rivi and harleys. thank you all for the helped.

arnulfo

[arnulfo de l.a.]

well men, i took off my distributor and located the little rubber stop on the counterweight stud. it was wore pretty thin so i made one out of some hard plastic tubing i had laying around.put the distributor back in , went for a test drive and WOW! I WOKE UP A BEAST! No mpre pinging and GREAT response on acceleration. i am one happy rivi owner. my next mission is to get the idle right by correcting *the throttle plate binding and finding the vacuum leak.

arnulfo