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Author Topic: What's this screw on 79 cb650 carbs  (Read 1761 times)

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Offline BollarNPS

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What's this screw on 79 cb650 carbs
« on: October 30, 2015, 07:52:59 AM »


Is this the screw to adjust when syncing carbs?
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Offline gloken

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Re: What's this screw on 79 cb650 carbs
« Reply #1 on: October 30, 2015, 07:55:16 AM »
I'm sure someone will correct me if I'm wrong.

Those Keihin PD carbs have a port to attach a manometer when you sync the carbs.  There should be one on each carb.
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Offline RevDoc

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Re: What's this screw on 79 cb650 carbs
« Reply #2 on: October 30, 2015, 07:57:17 AM »
Quote from: gloken on October 30, 2015, 07:55:16 AM
I'm sure someone will correct me if I'm wrong.

Those Keihin PD carbs have a port to attach a manometer when you sync the carbs.  There should be one on each carb.

Gloken, you are not wrong! ;D
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Dana

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Offline BollarNPS

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Re: What's this screw on 79 cb650 carbs
« Reply #3 on: October 30, 2015, 07:59:39 AM »
Great! Then next question is where are the adjusting screws.
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Offline gloken

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Re: What's this screw on 79 cb650 carbs
« Reply #4 on: October 30, 2015, 08:09:07 AM »
I thought this link had a good description of it:
http://www.motopsyco.com/2013/08/09/vintage-piston-valve-keihin-carburetor-overhaul/

When I did mine, I used a sheet called "How to remove, clean, rebuild, and reinstall keihin PD46a carbs"  by Brian Barnes, my bike's shop manual, and the manual that came with my manometer.

I think you'll want to understand how carbs work, and know your way around them, before you try to sync them. But that's just me.
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Offline BollarNPS

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Re: What's this screw on 79 cb650 carbs
« Reply #5 on: October 30, 2015, 08:12:29 AM »
Thanks a bunch sir!
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Offline flybox1

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Re: What's this screw on 79 cb650 carbs
« Reply #6 on: October 30, 2015, 08:12:56 AM »
Quote from: BollarNPS on October 30, 2015, 07:59:39 AM
Great! Then next question is where are the adjusting screws.
Either between 1/2 and 3/4 for screws with locknuts, or, under the top caps.
My 750K8's PD carbs have the adjuster screws under the caps.
My 350F carbs had them between the carb bodies. 
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Offline JimJamerino

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Re: What's this screw on 79 cb650 carbs
« Reply #7 on: October 30, 2015, 11:00:05 AM »
On the 650 they're under the top caps.
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~ Jim

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Offline BollarNPS

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Re: What's this screw on 79 cb650 carbs
« Reply #8 on: October 30, 2015, 11:55:02 AM »
meaning where the slides are? and may be a dumb question but its okay to run the bike with those tops off?
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Offline JimJamerino

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Re: What's this screw on 79 cb650 carbs
« Reply #9 on: October 30, 2015, 12:34:03 PM »
If you're looking straight down at the top of the carbs from a 79 or 80 CB650, there's 2 screws holding a lid on top of each carb. When you take that off, you can see the tops of the slides.

I wouldn't run without the top caps. You want the insides of your carbs to stay clean, and leaving the caps off will make that a tall order.
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~ Jim

formerly "emperorspartacus"

There are old bikers.  There are dumb bikers.  There are no old, dumb bikers.

My CB650C rebuild http://forums.sohc4.net/index.php?topic=74212.0

Offline BollarNPS

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Re: What's this screw on 79 cb650 carbs
« Reply #10 on: October 30, 2015, 12:56:48 PM »
Yeah I'm not talkin for long I'm just talkin about while vacuum syncing. Or do I run then shut off and make small changes and retry
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Offline Airborne 82nd

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Re: What's this screw on 79 cb650 carbs
« Reply #11 on: October 30, 2015, 01:03:39 PM »
Quote from: BollarNPS on October 30, 2015, 11:55:02 AM
meaning where the slides are? and may be a dumb question but its okay to run the bike with those tops off?

While syncing. Not riding :)
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