Non Starter question

[MattMcCoy]

Hold the idle jets up to a light. You should be able to see though them.

[yawjansen]

Yup! Did that multiple times...could it be the passageways themselves?

[desertrefugee]

Did you physically remove the slow jets from the tunnels? If not, they’re not clean. You can bet on it.

EDIT: Oops. Guess you did. Lots of carb cleaner and 100psi air. Clean, clean, clean. After that, it’s just a matter of configuration, i.e. adjustment - which is actually the easy part! (float height, idle mixture screws and synchronization)

...oh, and no air leaks!

[yawjansen]

Yeah, I did multiple times. Going to triple check all that as well as check float height. Otherwise, I'm pretty stumped. It's odd, both 2 and 4 having issues.

[redglbx]

Mix & matching different carbs usa very bad practice ! Again if you have spark on cyl’s 2 & 4 then you probably have plugged idle jets. If you Pull the idle mixture screws out you should be able to spray carb cleaner in the idle jets and it should come out of the idle mix screw hole, if not, it’s plugged. With the screws in it should also spray out of the tiny hole in the throttle bore.

[gltriker]

Mix & matching different carbs usa very bad practice ! Again if you have spark on cyl’s 2 & 4 then you probably have plugged idle jets. If you Pull the idle mixture screws out you should be able to spray carb cleaner in the idle jets and it should come out of the idle mix screw hole, if not, it’s plugged. With the screws in it should also spray out of the tiny hole in the throttle bore.

Although you may feel confident the removable #35 (.013"internal diameter ) slow fuel jets are not obstructed ,
I was also thinking about the probability that the pilot fuel discharge tube standing in the carburetor throat just downstream of the throttle plate might be obstructed, instead.

In your posts I haven't seen any mention of utilizing properly sized jet cleaners.

I don't have access to ultrasonic cleaning equipment.
With the carburetor disassembled to expose the internal circuits, I have utilized a very small diameter drill bit with my finger tips, only, to enter the open end of that brass pilot tube to plunge into the crap that will accumulate at the extreme bottom of that tube. Try that. Make sure the tiny discharge hole in the brass pilot tube is visible and pointed directly at the intake port, too.
Note ! The drill bit is a #62 micro bit. Same one I utilized to perform the off idle air jet correction.

Cover your eyes/face with protective gear when spraying aerosol cleaner to observe for the discharge of fluid out of that tube towards the open end of the carburetor throat.
FWIW, I have become very fond of utilizing just plain old alcohol in a trigger type oiler can to check after-cleaned flow through carburetor circuits and jets, etc. It delivers a large volume of liquid under a more controllable pressure.

Just thought of another item of concern!
If the fuel bowl gasket isn't sufficiently secured in place over the by-pass circuit aluminum puck and pilot tube supply passage, an external air leak path will be created into the 'idle fuel' delivery circuit. Stripped fuel bowl screws are #1 cause of that situation.

[gltriker]

Hey Paul, yeah, I've pulled the rack like 5 times so, no biggie there. Just pull it again...

Cliff, yeah the sync washers are in the correct position. Odd thing about the #1 carb, the sync screw is all the way in! It is the carb from a different set but is a 771A so should be good, odd though.

To pilot jets/passage ways clogged, their being clogged wouldn't stop the main jet from working correct? I'd assume at 3K RPM secondary jet would start responding and I should see a difference when I pull a plug, correct? Fuel is getting to the bowls at least.
Guess the carbs come off and I check float levels and idle jets and passageways again.

Your confirmation that the 2 flat washers are correctly oriented at their assigned locations and the synchronizer screw is all the way in takes me back to a set of 76 LTD carburetors I purchased for shipping cost only in 2017.

During one of its Previous Owners' disassembly reassembly sessions, the 2-4
carburetors' synchronizer assembly must have been incorrectly assembled and instead of correcting the error as a conscientious person would have done, had twisted the #2 throttle shaft's synchronizer lever out of alignment to make a Neanderthal assembly *correction * instead.

I wish I had taken a photo of the scene of this travesty.

Anyways I was blessed to have been successful to bend the lever back to its proper geometry and not damage the throttle shaft.
I removed the mangled adjuster screw and replaced it with all the required synchronizer parts from another set of 1976 carbs.
To my greatest relief, the synchronizer worked and adjusted exactly as designed.
Just putting the information out there.
Look over all the throttle components very carefully. Loose screws. Witness of
throttle shaft removal and incorrect reassembly issues. Such as Reversed or misaligned throttle shutter. Details Details Details.

[gltriker]

Cliff, yeah the sync washers are in the correct position. Odd thing about the #1 carb, the sync screw is all the way in! It is the carb from a different set but is a 771A so should be good, odd though.

Guess the carbs come off and I check float levels and idle jets and passageways again.

I had to know whether a replacement 771A carburetor was correct for a 1979 GL1000. According to Randakk and elsewhere, it is for all of the 1979 production.

[robin1731]

Cliff, yeah the sync washers are in the correct position. Odd thing about the #1 carb, the sync screw is all the way in! It is the carb from a different set but is a 771A so should be good, odd though.

Guess the carbs come off and I check float levels and idle jets and passageways again.

I had to know whether a replacement 771A carburetor was correct for a 1979 GL1000. According to Randakk and elsewhere, it is for all of the 1979 production.

Yes. That is the correct carb for late 78(emissions) and all 79 GL1000's.

[yawjansen]

Thanks Cliff and Robin for the confirmation of the correct carb swap!

Also, thanks for a more detailed description of the idle passageways and how to verify their condition! Removing jets and emulsion tubes, to me, has been the simple part. I've cleaned them out with brake cleaner, carb cleaner and ultrasonic. I've verified that all jets are open and to best of my knowledge, open the right amount with out inserting a cleaning device as it seems pretty not recommended? Cliff, I'll look into getting a hold of the recommended drill bit.
To the idle passageways themselves, after either soaking or ultrasonic, the best I've done is blow them out with compressed air, trying to feel or see where the air comes out then plugging with my finger to reveal another passageway. The idle/primary circuit is a bit of a maze! All the info above will help out greatly!
Last, I'll double check the position of the #1 carb linkage versus two other 771A bodies I have.
Thanks again!
Pat

[heraldhamster]

FWIW, the best way I've found to get those tiny drill bits is to buy a $10 pin vise that comes with a collection of different micro drill bits.
just use the drill bit between two fingers w/o the pin vise handle.
believe it or not, a pin vice is kinda handy to have sometimes.

[gltriker]

Fuel is getting to the bowls at least.
Guess the carbs come off and I check float levels and idle jets and passageways again.

Fuel pump output volume and operating pressure was already tested?

Done. For today.

[gltriker]

Thanks Cliff and Robin for the confirmation of the correct carb swap!

Also, thanks for a more detailed description of the idle passageways and how to verify their condition! Removing jets and emulsion tubes, to me, has been the simple part. I've cleaned them out with brake cleaner, carb cleaner and ultrasonic. I've verified that all jets are open and to best of my knowledge, open the right amount with out inserting a cleaning device as it seems pretty not recommended? Cliff, I'll look into getting a hold of the recommended drill bit.
To the idle passageways themselves, after either soaking or ultrasonic, the best I've done is blow them out with compressed air, trying to feel or see where the air comes out then plugging with my finger to reveal another passageway. The idle/primary circuit is a bit of a maze! All the info above will help out greatly!
Last, I'll double check the position of the #1 carb linkage versus two other 771A bodies I have.
Thanks again!
Pat

Mike Nixon and maaaaaaaaany other knowledgeable folks think otherwise. I believe with the proper jet cleaner wire you are cleaning and sizing and burnishing.
https://ngwclub.com/forum/viewtopic.php?f=54&t=76198

[yawjansen]

Haha! That's pretty funny! I'm cleaning and rebuilding a second set of 771A carbs and resorted to a high E guitar string to "help" clear out the slow jet on a couple of them. Guess it's one thing to see light through the jet orifice, another to have the proper opening size.
To the pump output, no, I'll round up a tee and see about that. One thing, all 4 bowls, when drained have the same amount of fuel in them. Don't know the volume, but it's the same when compared in four separate containers.

[gltriker]

You don't necessarily need a tee to perform the fuel pump pressure test. Remove the hose off the pump outlet and connect the pressure gauge directly onto that pump outlet fitting . You will know within seconds what the pump's cranking operating pressure is. Remember the link to the Shop Manual.
.