help needed with reassembling choke shaft

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juntjoo
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help needed with reassembling choke shaft

Postby juntjoo » Mon Jan 08, 2018 11:08 pm

here's a little vid

https://youtu.be/TuRg6Mwd0DM

Im just putting it back together for the first time and don't see how the shaft is supposed to be moved. I'd assume it would somehow be from the action of the that part that holds the choke cable and it's not affecting the choke shaft. I must have put something on wrong. Anyone know? Thanks
82" cb650 Nighthawk

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GeorgeSweety
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Re: help needed with reassembling choke shaft

Postby GeorgeSweety » Tue Jan 09, 2018 2:50 am

Hi juntjoo, I see from your vid that you have already installed the choke plates (butterflies), you need to remove them and then try to operate your choke pulley. Your choke plates (butterflies) should only be put in when the rack is together as they can stick in the carb body. They should be loosely screwed in at the end of the build, then while you operate the choke pulley you move from screw to screw slightly tightening each one until all four choke plates operate smoothly. When you are happy with the movement and it operates smoothly, remove only one screw from each choke plate and apply some Loctite Semi Permanent to the screw and replace it but keep checking the choke action as you do it, leave for an hour or so then remove the other screws from the choke plates and apply Loctite to those as well. It is very important to keep checking the choke operation to make sure the plates do not bind in the carb bodies.
If you think that you have assembled the choke pulley wrongly then I will get my camera and take close up pictures of my CV carbs, they are already off the bike but I haven't been near them with a screwdriver yet :D

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GeorgeSweety
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Re: help needed with reassembling choke shaft

Postby GeorgeSweety » Tue Jan 09, 2018 4:37 am

CV Carb choke pulley 001.JPG
CV Carb choke pulley 001.JPG (126.67 KiB) Viewed 944 times
CV Carb choke pulley 002.JPG
CV Carb choke pulley 002.JPG (139.52 KiB) Viewed 944 times
CV Carb choke pulley 003.JPG
CV Carb choke pulley 003.JPG (141.25 KiB) Viewed 944 times

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Folsoml
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Re: help needed with reassembling choke shaft

Postby Folsoml » Tue Jan 09, 2018 7:10 am

George's pictures show perfectly how the choke shafts are supposed to come together, and how the spring should attach. His carbs are different than yours, but the choke works the same.

I always urge anyone with the VB carbs (like yours) to follow along with the MacGregor Manual (http://www.cb750c.com/publicdocs/SeanG/ ... l_revG.pdf). SeanG describes in great detail how the carbs are supposed to come together and how to ensure that the choke plates open and close smoothly. Check around page 32 or so.

PS: Do not take George's advice on the thread locker lightly. The screws holding the choke plates are very small. Vibration could easily cause one to back out. If this happens, it is very likely that it could get sucked into the engine--causing all kinds of havoc.
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GeorgeSweety
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Re: help needed with reassembling choke shaft

Postby GeorgeSweety » Tue Jan 09, 2018 9:31 am

Hi Folsoml, the carbs in the pictures are VB44C's from my 82 Nighthawk. I know I'm always bangin on about my PD carbs but I just haven't got around to doing anything with these VB's yet :) ....................must cut those damn nails one day!

juntjoo
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Re: help needed with reassembling choke shaft

Postby juntjoo » Tue Jan 09, 2018 11:38 am

GeorgeSweety wrote:Hi Folsoml, the carbs in the pictures are VB44C's from my 82 Nighthawk. I know I'm always bangin on about my PD carbs but I just haven't got around to doing anything with these VB's yet :) ....................must cut those damn nails one day!


thanks a lot. and mine actually match up with yours and I do have the guide but this section is confusing the first time for me at least. anyway, but my issue is that when I move the lever the cable attaches to it doesn't move the choke shaft/plates. so maybe that's on purpose? if not please enlighten me on how the shaft ultimately get turned but it doesn't matter really. I just need to know what to fix or just proceed forward. Thanks!

and thx for the loctite suggestion. i wondered about that
82" cb650 Nighthawk

juntjoo
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Re: help needed with reassembling choke shaft

Postby juntjoo » Tue Jan 09, 2018 11:41 am

Folsoml wrote:George's pictures show perfectly how the choke shafts are supposed to come together, and how the spring should attach. His carbs are different than yours, but the choke works the same.

I always urge anyone with the VB carbs (like yours) to follow along with the MacGregor Manual (http://www.cb750c.com/publicdocs/SeanG/ ... l_revG.pdf). SeanG describes in great detail how the carbs are supposed to come together and how to ensure that the choke plates open and close smoothly. Check around page 32 or so.

PS: Do not take George's advice on the thread locker lightly. The screws holding the choke plates are very small. Vibration could easily cause one to back out. If this happens, it is very likely that it could get sucked into the engine--causing all kinds of havoc.


thanks
82" cb650 Nighthawk

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GeorgeSweety
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Re: help needed with reassembling choke shaft

Postby GeorgeSweety » Tue Jan 09, 2018 12:07 pm

juntjoo wrote:
GeorgeSweety wrote:Hi Folsoml, the carbs in the pictures are VB44C's from my 82 Nighthawk. I know I'm always bangin on about my PD carbs but I just haven't got around to doing anything with these VB's yet :) ....................must cut those damn nails one day!


thanks a lot. and mine actually match up with yours and I do have the guide but this section is confusing the first time for me at least. anyway, but my issue is that when I move the lever the cable attaches to it doesn't move the choke shaft/plates. so maybe that's on purpose? if not please enlighten me on how the shaft ultimately get turned but it doesn't matter really. I just need to know what to fix or just proceed forward. Thanks!

and thx for the loctite suggestion. i wondered about that


The choke shaft is only connected to the choke pulley by the spring, it is only the tension of the spring that turns the choke shaft. If one of your choke plates is slightly "off" it will stop the choke shaft from turning. I like to assemble the rack first to make sure the choke shafts are connected properly before I fit the choke plates. I am actually building a rack right now as I type this :lol:

juntjoo
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Re: help needed with reassembling choke shaft

Postby juntjoo » Tue Jan 09, 2018 12:39 pm

GeorgeSweety wrote:
juntjoo wrote:
GeorgeSweety wrote:Hi Folsoml, the carbs in the pictures are VB44C's from my 82 Nighthawk. I know I'm always bangin on about my PD carbs but I just haven't got around to doing anything with these VB's yet :) ....................must cut those damn nails one day!


thanks a lot. and mine actually match up with yours and I do have the guide but this section is confusing the first time for me at least. anyway, but my issue is that when I move the lever the cable attaches to it doesn't move the choke shaft/plates. so maybe that's on purpose? if not please enlighten me on how the shaft ultimately get turned but it doesn't matter really. I just need to know what to fix or just proceed forward. Thanks!

and thx for the loctite suggestion. i wondered about that


The choke shaft is only connected to the choke pulley by the spring, it is only the tension of the spring that turns the choke shaft. If one of your choke plates is slightly "off" it will stop the choke shaft from turning. I like to assemble the rack first to make sure the choke shafts are connected properly before I fit the choke plates. I am actually building a rack right now as I type this :lol:


that little spring? if I have my carbs touching each other at the top and bottom sides where they touch shouldn't the shaft move freely enough (for that little spring to move it)? When I hold the choke pulley out of the way to feel the resistance of the shaft it's got a little resistance, enough to resist the spring. So that's too much then? It's gotta be completely free? I wonder what is binding it

edit: never mind. i see my misunderstanding now. the shaft moves off the little spring but off the 3/4 pair that i havent connected yet. spring moves 3/4, 3/4 moves 1/2

but my 1/2 pair does have some resistance. once tho you've bolted the brackets on that should squeeze them where they need them no?
82" cb650 Nighthawk

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GeorgeSweety
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Re: help needed with reassembling choke shaft

Postby GeorgeSweety » Tue Jan 09, 2018 2:06 pm

Have you removed the choke plates? If they are still in place and one of them is binding it could cause enough resistance to prevent the choke shaft from turning.

juntjoo
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Re: help needed with reassembling choke shaft

Postby juntjoo » Tue Jan 09, 2018 2:42 pm

GeorgeSweety wrote:Have you removed the choke plates? If they are still in place and one of them is binding it could cause enough resistance to prevent the choke shaft from turning.


I'm just about to take them (3/4) apart again because those turn first then1/2. I'm still confused about how free they need to be. must be like totally right? i dont remember them being that loose but right now the 3/4 is pretty free. ill see in a bit...
82" cb650 Nighthawk

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GeorgeSweety
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Re: help needed with reassembling choke shaft

Postby GeorgeSweety » Tue Jan 09, 2018 3:25 pm

If the choke plates are still in place then just slacken all the screws, try the choke pulley to see if it still binds. If it does then you will know it is the pulley mechanism and not the plates.

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Folsoml
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Re: help needed with reassembling choke shaft

Postby Folsoml » Tue Jan 09, 2018 7:21 pm

GeorgeSweety wrote:Hi Folsoml, the carbs in the pictures are VB44C's from my 82 Nighthawk.


Ahhh. I see that now!

juntjoo wrote:but my 1/2 pair does have some resistance. once tho you've bolted the brackets on that should squeeze them where they need them no?


The carbs are not really designed to operate the choke plates until they are fully assembled. Without the brackets holding them together, the slightest misalignment could cause them to bind up. If you read that Macgregor Manual, it has a section on reassembling them--including a step by step bolt-tightening process specifically to ensure that the choke plates open and close as they should.
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juntjoo
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Re: help needed with reassembling choke shaft

Postby juntjoo » Wed Jan 10, 2018 4:14 pm

GeorgeSweety wrote:If the choke plates are still in place then just slacken all the screws, try the choke pulley to see if it still binds. If it does then you will know it is the pulley mechanism and not the plates.


That's it. thanks much George. That was the key and the first thing I should have done. Dont know if that should be a rule in general but apparently I did everything right putting the halves together and just needed to do this last tightening step. And it was difficult following the guide step by step as it had you do all kinds of unnecessary acrobatics w/ a paper clip or something + the carbs arent exactly mine. But for the most part it was easy to follow. so hopefully that was the toughest part of this. Probably not. So often it's just ignorance of what happens next so you proabably have to do a rebuild one a few times to cover the most common challenges. Do this a few times actually I could see viable niche side hustle here. The neighborhood's trusty motorcycle carb rebuilder. If I had the cash and knew how extensive 'cleaning up your carbs' would be I might pay someone a few hundred to do theirs over the weekend. Anyway...
82" cb650 Nighthawk

juntjoo
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Re: help needed with reassembling choke shaft

Postby juntjoo » Wed Jan 10, 2018 4:14 pm

Folsoml wrote:
GeorgeSweety wrote:Hi Folsoml, the carbs in the pictures are VB44C's from my 82 Nighthawk.


Ahhh. I see that now!

juntjoo wrote:but my 1/2 pair does have some resistance. once tho you've bolted the brackets on that should squeeze them where they need them no?


The carbs are not really designed to operate the choke plates until they are fully assembled. Without the brackets holding them together, the slightest misalignment could cause them to bind up. If you read that Macgregor Manual, it has a section on reassembling them--including a step by step bolt-tightening process specifically to ensure that the choke plates open and close as they should.


thank you. that's exactly what I wasn't understanding. got it all working now.
82" cb650 Nighthawk


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