Topic: '82 CB650 Questions Super-thread

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I've been trying to get my '82 CB650SC NIghthawk running smoothly for a while now, and have had to make multiple threads to find answers to my problems. I figured I'd make one big thread with answered/needing to be answered questions to keep the boards clean as well as archiving a list of basic questions for other newbies.

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Current question(s)

Does turning the pilot screws out richen or lean the fuel/air mixture?
How would I clean my wiring harness? What kind cleaner would I use?

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Questions answered

Bench Syncing VB44c -                                                    http://forums.sohc4.net/index.php?topic=41326.msg426152#msg426152

Syncing VB44c Carbs -                                                     http://forums.sohc4.net/index.php?topic=40870.msg420962#msg420962

Putting together the choke lever on your handlebar -      http://forums.sohc4.net/index.php?topic=40851.msg420725#msg420725

Idling Speed Issues -                                                         http://forums.sohc4.net/index.php?topic=40849.msg420690#msg420690

Alternate Carb Adjustment Tool / Adjusting Cam Chain - http://forums.sohc4.net/index.php?topic=40828.msg420471#msg420471

Bike Won't Turn on -                                                           http://forums.sohc4.net/index.php?topic=40769.msg419861#msg419861

Rebuilding VB44c Carbs                                                     http://forums.sohc4.net/index.php?topic=40641.msg418381#msg418381

Charging System Woes                                                      http://forums.sohc4.net/index.php?topic=40477.msg417996#msg417996

                                                                                                     http://forums.sohc4.net/index.php?topic=39605.msg410367#msg410367

[WFO]

'82. I mean vacuum port. Pretty new stuff to me. All 4 are available but the second port has a connector from the accelerator pump screwed into it. Any ideas?

I checked my carb sync yesterday and i just disconnected that vaccum tube and slide the tube from my carb sync tool and it worked fine.

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'82. I mean vacuum port. Pretty new stuff to me. All 4 are available but the second port has a connector from the accelerator pump screwed into it. Any ideas?

I checked my carb sync yesterday and i just disconnected that vaccum tube and slide the tube from my carb sync tool and it worked fine.

I figured out how to sync them with a manometer, but I'm wanting to know how to bench sync them.

[WFO]

I found this on bench syncing...


http://www.sohc4.net/index.php?title=FAQ
When I rebuild a set of carbs, I always bench sync them before I re-intall them. Basically, I use a 1/8" drill bit as a gage.

Here's how you do it:

Adjust the idle screw (the main one) until the 1 carb outside of it is open enough to just let the 1/8" drill bit through.
Then adjust the _sync_ screws on the other 3 carbs until the drill bit just fits them as well.
You'll probably want to close the idle screw before you bolt them back on the bike, 1/8" openeing is pretty big.
This isn't a perfect sync, as there are other things that will affect the airflow to a given cylinder, but it will get you pretty close.
Comment from Bob Wessner: I was reading the FAQ's, on carbs to be specific, about bench syncing. It's probably trivial and only affects those with pre-K1 750's, but they really can't be bench sync'd off the bike because of the four independent cable linkage. I must have read through I don't know how many earlier posts on this trying to figure out how it would possibly help on mine until it dawned on me that as described, it only works for models that have the carbs all linked via the bar, so to speak. Jus thought may a note to the affect that the described procedure is for K1's and later might be useful.

[Logite]

I found this on bench syncing...


http://www.sohc4.net/index.php?title=FAQ
When I rebuild a set of carbs, I always bench sync them before I re-intall them. Basically, I use a 1/8" drill bit as a gage.

Here's how you do it:

Adjust the idle screw (the main one) until the 1 carb outside of it is open enough to just let the 1/8" drill bit through.
Then adjust the _sync_ screws on the other 3 carbs until the drill bit just fits them as well.
You'll probably want to close the idle screw before you bolt them back on the bike, 1/8" openeing is pretty big.
This isn't a perfect sync, as there are other things that will affect the airflow to a given cylinder, but it will get you pretty close.
Comment from Bob Wessner: I was reading the FAQ's, on carbs to be specific, about bench syncing. It's probably trivial and only affects those with pre-K1 750's, but they really can't be bench sync'd off the bike because of the four independent cable linkage. I must have read through I don't know how many earlier posts on this trying to figure out how it would possibly help on mine until it dawned on me that as described, it only works for models that have the carbs all linked via the bar, so to speak. Jus thought may a note to the affect that the described procedure is for K1's and later might be useful.

It seems as though I can only get one of the throttle plate openings opened enough for a 1/8th drill bit to fit through.

How odd...

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To bench-sync the carbs I just turned the idle screw all the way in, used a feeler gauge of .05 mm to slip them through the front of the carbs' throttle plates and adjusted them all from there. You could also use the same method on any other carbs by checking the clearance of the 2nd carb (the one with the accelerator pump mechanism) It Should be pretty accurate

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