carb problem

I need suggestions where to go from here

81 Yamaha XJ650 Maxim
I just completed rebuilding my carbs.
I tore them down completely
broke the carbs apart into individual carbs
removed everything jets etc...
used carb cleaner, wire tool, and air to clean all passages
ultra sound cleaned carbs
soda blasted carbs
cleaned all with carb cleaner
reassembled

The bike started up within a second or two on prime / switched to on
i set the idle / idles at 700 well
revs and snaps back

I start on a test ride and it bogs when accelerating hard

I got brand new gas
I changed the oil
I changed the spark plugs
I put seafoam in gas
I tried turning fuel mixture screw in 1/2 turn all 4 carbs
I tried turning fuel mixture screw out 1/2 turn all 4 carbs
I tried running in prime petcock
I tried running in reserve petcock

It seems better after spark plugs were changed / but still not strong acceleration / some popping not much
It sounds good revving in neutral

I need suggestions where to go from here

the bike was running good before I started / but leaking gas
I replaced the needle and seat
I replaced the O-rings in the gas pipes between the carbs / this was the problem I think / no gas leaking now

Thank you in advance for any advice you have for me.

I have rebuilt / clean carbs on this bike several times and on my 81 Honda CB750K many more times than I like to admit.

Stevenolts

 

Did you bench sync the carbs on assembly and then do a running sync with gauges?

 

I don’t see anything about syncing, or float height, or colortuning…….

 

what is color tuning?
I will sync the carbs / that was next on my list / I have sync tool /
If I need to take the carbs back off I will check the float height

Thank you!!!

This carb ran great on the bike when I took it off
it was cleaned about a year ago
it was leaking so I figured if I was taking it off to replace the O rings in the carb connection pipes I would clean extra good this time

 

https://www.gunson.co.uk/techtorque/Colortune-See-inside-the-combustion-chamber

 

This would have required a reset of the float levels, or better yet a wet set to get the proper fuel level

https://www.xj4ever.com/setting fuel levels.pdf

 

If you log on and click the xjforever icon top right, you can access a mine of information, including carb setting and cleaning. As well as searchings on carbs issues. You will quickly gather that 90% of issues with these old bikes is carb related, sometimes because they are old, dirty, or issues caused by owners. They are all vacuum operated devices, and little understood. Even when you do understand them, they can take a while to sort.

 

Thank you for your advice
I am off tomorrow
I will take another look

Thank you,
Stevenolts

 

Did you do an air pressure check to make sure the diaphragms were seated? That too would cause bog issue.

 

That is where I landed today

I need to spray carb cleaner around the air box boots to see if they are leaking.
If not I need to remove the carbs and check the diaphrams.

If I need new diaphrams where can I get them?

----------------------------------------------------

I have it idling great
revs snaps back

I just synced the carbs as best as I could
(I have the motion pro round gauges / the bounce but when I rev a little they all seem the same after adjusting)

I started with air fuel screws 2.5 out
I went 1 out through 4 out testing each adjustment (no change still bogs)

I now think it must be an air leak
diaphram slides or airbox boots

Thank you, Stevenolts

 

What is the correct way to do the pressure check
blow air in the vent to raise the slide?

Thank you, Stevenolts

 

It runs and starts so good just to bog at 3/4 throttle
if I shift quick it goes until I hit 3/4 throttle

What is the best way to adjust the air fuel mix after I get rid of the bog?

Stevenolts

 

Once you get out of the idle circuit. The fuel mix screw is not a big factor.
Then it is the main jet and slide needle.
Hitachi needle are a set height so you are looking at your jet size, compression, air filter and exhaust flow.

If the slide opens the main jet and it is too big then you flood... And the opposite if too small of course.

Are your main jets standard?

 

They are stock with the stock air box
Stevenolts

 

A couple of tricks.
Pull the slides and hold the diaphragms up to a light and look for holes.
If the air filter is new, stick a piece of cardboard over the air inlet with a smaller hole in it to restrict air flow to test.
If it's not new blow it out with a compressor or leave it out for a short test.

Do you have the standard 4into2 exhaust system and standard mufflers?

What compression numbers do you have?

 

Bogging rich or bogging weak? I suspect weak, otherwise you would know...
Did you forget to fit the springs above the slides?
Did you fit the air jets in the wrong place - the Haynes manual has them the wrong way around, or so I have read on here....

 

I sprayed carb cleaner on airbox boots and intake boots no change in idle

I took the carbs off
I sprayed air in intake slot and only 1 of 4 slides moved up
I took the caps off and reseated the diaphragms and now all 4 slides go up with air sprayed in

As good as this bike ran with 1 of the 4 slides just bog

I think once I put the carbs back on tonight and test it should run very well.

Thank you for you help
Stevenolts