Hesitation and Bogging Issue when under load

[Flarrow13]

I have a 1982 Honda CB650SC Nighthawk that I acquired last year. The bike originally did not run but after 2 carb cleans and a carb rebuild kit, the bike now starts and idles perfectly. The only problem I am having now is when giving the bike a lot of throttle quickly, it hesitates and bogs down. It starts doing this in 2nd gear, and will gradually get better when I am in different gears. When I cleaned the carbs, the only thing I really did not touch was the fuel rail on the carbs, maybe that has something to do with it? It should also be known that I replaced plugs, plug wires, accelerator pump, and ignition coils. Any help would be greatly appreciated as I am at a dead end with it. Like I said, the bike idles just fine and when giving it a lot of throttle quickly when idling, it has zero issues.

[mollusc]

Did you change the air filter?  You don't mention that.
Also, did you do a bench sync while you were cleaning the carbs?  What did you set the mixture screws to?  Did you do a vacuum tune after you reinstalled everything?

[Pete in PA]

Any time you go through pulling the carbs to clean them also richen the mid range with a small washer under the needle at the same time. Maybe even go 1 size larger on the main jet.

Do some research on your particular bike as to what works.

The EPA has strangled bikes since the beginning.

[Flarrow13]

I did not change the air filter as the owner of the bike replaced the air filter back in early 2020. I did a bench sync and Vacuum Sync. I may try going with a larger main jet next to see if that doesn't fix the problem.

[draser]

Is the airbox stock? If your carbs are CV carbs, vacuum operated slides, they will not work well without airbox. If airbox is stock, I'd check the slides by pushing up and release, they all should come down the same, somewhat slow. If any of them come down faster the diaphragm is pinched - not installed right. If all slides move down the same then the vacuum port that activates them is blocked or partially blocked. Also, check float level if adjustable.
Changing jets in stock form just covers up the problem.

[Flarrow13]

I believe the airbox is stock on it. I do have the vacuum operated slides, I will have to take a look at the slides and see how fast they come down. The bike does not hesitate at all if I goose the gas while the bike is idling, but I will look into it. Thanks for all the help

[Flarrow13]

Also, from what I can remember the slides seemed to drop rather quickly, but all at the same speed. So I will also take a look at the vacuum ports. Say the ports are blocked, what is a good way to clear them?

[draser]

At idle, the fuel requirement is rather low, as opposed to at load. If all slides drop the same it's unlikely they're all pinched. Then again, there should be some slowness in the way they come down due to air having to escape the vacuum port.
Since they come down "rather quickly" the vac ports are open (assuming the caps are on tight).
What about the carb boots in and out the carbs? No cracks, carb set all in, clamps tight? Use a propane torch turned on low and see if idle changes when moving torch about the boots.
I'd then check the fuel level in bowls - being an 82 I'm guessing the level is adjustable (like my Magna), is level correct?
Finally, any fuel filters, is fuel flow good going into carbs? It seems you have a screen part of petcock assy, I'd check that. You also have a automatic fuel valve, is that vacuum actuated and shuts off fuel when bike don't run? For now I'd bypass and see if it makes a diff. 

[Flarrow13]

The boots seem to be tight, but I will try running a torch by them to see if I can get the idle to change at all. The floats on this bike are pure plastic so they are unadjustable. I am not sure if the fuel valve is vacuum actuated or not, I will have to look into that, but for now I will try everything you suggested. Thanks for the help

[draser]

To recap - this problem can be broken down into 2 - vacuum and fuel flow. Both are critical, because vacuum raises the slides and you want that to be linear (no flat spots) and fuel needs to get into bowls rather quickly and then up into carb throat via jets.
Now, reading your post again, if this is worse in second gear and kinda goes away as you change in higher gears it may be that your pilot jet that's not totally clean - as you twist throttle you have pilot jet supplying fuel at idle (but idle is good) then at 1/4 throttle you have full pilot jet flow and some main jet flow, then as you throttle up more you're transitioning into the main jet (pilot not that relevant).
So, I'm thinking your pilot jet is/may be clean enough for idle but not totally clean for second gear flow requirement... I know a guy who has a carb cleaning business, he's actually running pin gauges thru the jets to ensure they are fully clean/open (to spec) for correct fuel flow.
I normally use copper wire strands and run them through jets, emulsion tubes and carb ports (after running carb through my ultrasonic cleaner). Then I blow compressed air ensuring it comes out the other side of carb passages.
When I started up my 82 Magna, after cleaning carbs and fuel tanks (or so I thought) bike started up fine, and I went for a short ride. I left home fine then bike started bogging down worse and worse and ended up pushing the bike back. Removed carbs and they were filled with junk from my fuel tanks which I thought were clean. Cleaned tanks again (Magna has a reserve tank) and lots of junk came out. I used vinegar to remove surface rust in tanks, which worked great on rust but done nothing on the gunked up old gas. Ended up running acetone through tanks several time until it came out clean. Been good since (5 yrs ago).
Carb stories...