Topic: Please help, need to reset sync to factory, CB550

[Kframe]

So today I was trying to sync my carbs on the 74 550 K0, and two were waaaay off, so I followed some directions I found online that said I could turn all four adjusters clockwise until closed, back off 1 turn, and start the bike and go from there. 

Well, I backed off the locknuts most of the way and started turning the screws clockwise, but they never bottomed.  I can turn them with very little force until they're down to the raised locknut again.

So, now I've really got them screwed up.  Is there a way to set them to a baseline? 
I really really don't want to have to remove the carbs from the bike to bench sync them.

Is there a way to "reset" them on the bike?  According to the website here they are Keihin Type 1 carbs for the 74.

Thanks!
-Kris

[OldSchool_IsCool]

Can you start the bike?  If yes, do you have a sync meter?  If no to both, I think a bench sync is in your future.

[Kframe]

Thanks for the reply.
The bike starts but races right up to 5000rpm!
The idle speed thumbscrew is backed off, so I think it's a very lean condition causing the surge. (I'm guessing. )

My vacation meter is a homebuilt oil(ATF) 4 channel manometer.
The vacation is so unbalanced that all of the fluid is agitated into a froth in one second, so I can't even tell where to start.
(I've used manometer before with good results so I don't think that's the problem. )

If I have to pull the rack out it turns into a whole day job, and it's supposed to be gorgeous here tomorrow and I'd like to spend it riding not wrenching! 
Any tips would be greatly appreciated.
Thanks, -K

[mlinder]

Just push the reset button...





lol, sorry.



Look, you have to synch your carbs with a carb synch tool.
For the time being, search for "bench synch" here on the forums. This will get you in the ballpark, and back on the road until you do a real carb synch.

[OldSchool_IsCool]

There is likely one or two sliders that are WAY open, thus the high rev despite backing out the idle screw.  You could cross your fingers and guess which one(s).  Getting eyeballs on the actual silde opening is the reason you need to think about the bench sync. 

Unless you can see the slides through the filter box and can judge which is way wacky.

[Kframe]

Just push the reset button...





lol, sorry.



Look, you have to synch your carbs with a carb synch tool.
For the time being, search for "bench synch" here on the forums. This will get you in the ballpark, and back on the road until you do a real carb synch.

No reset button, maybe I should go to Staples?   


Dang.

I hoped I wouldn't have to pull the rack.   

I don't know why my sync tool wouldn't work worse than a store-bought manometer.
Or are you talking about vac gauges? 

I think I'll play around for another hour or so in the morning, and if I can't get things smoothed out I'll pull 'em. 

It's in the 70's here in MN, which in March is a rare gift - gotta get this sorted quick!

Thanks, -K

[OldSchool_IsCool]

Just push the reset button...





lol, sorry.



Look, you have to synch your carbs with a carb synch tool.
For the time being, search for "bench synch" here on the forums. This will get you in the ballpark, and back on the road until you do a real carb synch.

No reset button, maybe I should go to Staples?   


Dang.

I hoped I wouldn't have to pull the rack.   

I don't know why my sync tool wouldn't work worse than a store-bought manometer.
Or are you talking about vac gauges? 

I think I'll play around for another hour or so in the morning, and if I can't get things smoothed out I'll pull 'em. 

It's in the 70's here in MN, which in March is a rare gift - gotta get this sorted quick!

Thanks, -K

I feel ur pain.  Good luck with the fiddling!

[Kframe]

I feel ur pain.  Good luck with the fiddling!

Thanks, I'm gonna have to get more bandaids if I plan on pulling the carbs.
It's brutal on the knuckles!
 
-K

[OldSchool_IsCool]

Best way to do it I've found is to REMOVE the clamps, not just loose, but OFF the boots completely.  Push the softer intake boots (filter side) up and off the bottom of the carb throat.  Twist the carbs down so that the engine side of the carbs pull free from the TOP of their boots.  Wiggle the bank out.

Install in reverse order.

"Golf Words" are inevitable.

[Kframe]

Best way to do it I've found is to REMOVE the clamps, not just loose, but OFF the boots completely.  Push the softer intake boots (filter side) up and off the bottom of the carb throat.  Twist the carbs down so that the engine side of the carbs pull free from the TOP of their boots.  Wiggle the bank out.

Install in reverse order.

Ah ha!  I knew there had to be some technique to make it a bit easier.  Thanks, that helps!

"Golf Words" are inevitable.

You ain't kidding.  I remember last time.  But hopefully I can do this easier and quicker 2nd time around.

-K

[steamnjn23]

in addition to what "old school' said, i install my center boots first, then the 2 outer boots.  come up from the bottom.  you'll also notice on the outer boots there is a dimple in the rubber and it lines up with the dimple on the air box. put a dot of white marker on them to make them easier to see   

it takes me appx 15 minutes to R&R the carb bank.  now if the other work could be completed as quick...

[Kframe]

in addition to what "old school' said, i install my center boots first, then the 2 outer boots.  come up from the bottom.  you'll also notice on the outer boots there is a dimple in the rubber and it lines up with the dimple on the air box. put a dot of white marker on them to make them easier to see   

it takes me appx 15 minutes to R&R the carb bank.  now if the other work could be completed as quick...

Awesome, thanks!  Hopefully I don't get enough practice to make it a 15min job!
I like to tinker, but that's what winter's for, now it's time for riding!

-K

[Kframe]

When I get to the point of actually vac syncing them, the manual states that clockwise increases vacuum, ccw decreases vacuum to the port.
So is the slide going up or down to increase the vacuum "pulled" at the port?
Thanks, -K

[TwoTired]

So today I was trying to sync my carbs on the 74 550 K0, and two were waaaay off, so I followed some directions I found online that said I could turn all four adjusters clockwise until closed, back off 1 turn, and start the bike and go from there. 

Jeez, you got screwed taking that advise.  Reminds me of the video clip where the father is showing the tyke how the video tape machine "eats" video tapes.  Later the tyke feeds the video machine much better tasting mashed potatoes right into the tape slot.

So, now I've really got them screwed up.  Is there a way to set them to a baseline? 
I really really don't want to have to remove the carbs from the bike to bench sync them.
Is there a way to "reset" them on the bike?  According to the website here they are Keihin Type 1 carbs for the 74.

No, you don't have to take them off the bike to get them functioning again.  But, you will have to develop a feel for when the slide bottoms in the bore.  Right now you have skewed all the adjustments so that the slides cannot close, and that is why the engine races.

Back off the big idle adjust knob to be certain that it can't block the throttle open even a little.
Pick a carb to start from, say # 1.    Remove the top of the carb so you can see the arm and top of slide inside the carb body. 
Now move the slide position adjuster and watch the slide move down the bore and stop adjusting when its downward travel ceases.  This should be the point at which the slide has completely closed off all air flow to the cylinder. Lock that adjuster down and don't move it ever again.  Slap your own hand if you reach for it. .... HARD.

You have two options for getting the others synched.
1.  Move the other slides down in the bore the same way you did the first carb, until they *just* seat at the bottom of the carb throat.
This is a very coarse adjust.  You will still need to vacuum sync the remaining three carbs to the reference carb (#1 remember?).

2. If the engine will get somewhere close to idle (using the big idle knob), you can adjust the vacuum of 2,3, & 4 carbs to whatever the vacuum reading is of #1, at which point you have the carbs vacuum synched.


Think about what the idle knob does.  It keeps all the slides from closing off all the air to the engine.
If you actuate the idle stop knob, you should be able to make the slides move up in the ways of the carb just enough to get an idle.  However, if all the adjusters are skewed so that the slides can bottom, the idle knob no longer dominates the idle stop position of the slides. (and is why the engine now idles at 5000 RPM.)

Cheers,,

[Kframe]

Jeez, you got screwed taking that advise.  Reminds me of the video clip where the father is showing the tyke how the video tape machine "eats" video tapes.  Later the tyke feeds the video machine much better tasting mashed potatoes right into the tape slot.

No, you don't have to take them off the bike to get them functioning again.  But, you will have to develop a feel for when the slide bottoms in the bore.  Right now you have skewed all the adjustments so that the slides cannot close, and that is why the engine races.
.......
Cheers,,

Thank you very much, with your detailed procedure I was able to get the bike running and rough sync'd, and then I used the manometer to get it closer.  I do think I will splurge and get a ready-made bank of sync gauges when I can afford it, the homemade manometer works but is a hassle.

Yes indeedy, I got screwed on the advice I read, whodathunk, you can't believe everything on the internet, I'm shocked!   
I read that "tip" here ----> http://www.hondahobby.no/website.aspx?displayid=1593  and under #9 it states you can reset by going all the way clockwise and then out 1 turn, which really really didn't work. 

Well, I just went and got tabs and insurance, the lady at the DMV was surprised at its age and that the last time it was tabbed was in 1985!  She wanted to charge me registration for the past 25 years but I had a letter from the PO stating its non-use. 
That saved me $250!    

Time to go riding!

Thanks again to everyone that helped!
-K