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Discussion Starter #1
Stattz waiting for an updtae on your new machine ...
George
 

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All is not well in paradise. Because she was idling around 4000 rpm I thought that she might be getting too much air in the idle mixture. The idle mix screw had no affect so I took off the carb rack and noticed that the valve slides on cylinders 1 & 4 had larger gaps than 2 & 3. So I tried to adjust them using the little screw on the top of the linkage. Error.

Now she won't run at all. The manual says nothing about adjusting the slides, only to be careful to reassemble the right way round. I also noticed that cylinder 2 does not have that adjusting screw. ( I used that slide as a reference and tried to match the others to it. If I adjust one of the slides (say #4) then as 4 reaches bottom the other slides start to rise. What's going on there? I don't know. I think I may need a pro do to this bit for me unless there's something I don't know that could make the difference.

I'm a bit reluctant to open up the carbs completely as they don't match the ones in the manual (wouldn't you know it) and who knows what I might screw up through ignorance.

Stattz
 

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don't know about the 1978 carbs but the 1974 carbs have a way of adjusting the slide on the needle in addition to a way of synching the carbs up. Sounds like you are trying to adjust the carb synch instead of the slide on the needle. the gurus at sohc4.net might know a little better so ask over there. The slide should not be totally closed or the bike will not run, they should probably be 1/8th of an inch open (just guessing here).
 

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theres a reason the pros charge and arm and a leg for working on those things. they are a p.i.t.a.!

my 77 is finally running good, i just kept running 93 pump through it. about 3000k later on the clocks and its running pretty good.

jc
 

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Discussion Starter #5
did seem like to much air your not far off course dont freal out calm and patience ..you need to ask for help my friend we can put you in the right direction can you shot a pic of the carbs to us may be we can tell you what you working on ...you can do it dont get a pro yet .....steady Stattz steady put the phone down and step back slowly very slowly we are here to help
 

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also, chances are, messing with the screws wont solve anything. it was running when it came from the factory. if someone decided to start randomly turning the screws after that, then chances are you wont get it figured out without going back to the factory settings and seeing if it'll run. the problem that presents is if it doesnt run. then you have to start looking again. i usually dont start messing with the screws until ive checked everything else. float valves, jets, etc. cuz once youve messed with the screws, with out indexing them or making sure you keep really close track, you can be opening a huge can of worms. those racks of carbs can be a major pain. and you gotta have some idea what youre doing before you start digging in. good luck. and keep us posted.

jc
 

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Discussion Starter #7
hold on ....guys carbs are not the big sink hole ,most people freak out because they are two or three or four carbs.

a bike is simple ,a bike has one carb per cylinder
A cylinder requires air and fuel.

Now stop thinking for a minute. You dont have to figure ANYTHING out ...its ALREADY figured out for you what it needs.

All you have to do is leave them alone.

but when some one starts playing with them they have ussually twisted things out of wack...NOW

There are only two things they did 1 to much or too little air
2 to much or two little fuel

just because you have four carbs, the mind, doesnt have to go crazy!

just think if no one has messed with the linkage all you have to do is unscrew! each air screw back them all the way out

then unscrew each fuel screw all the way out/or all the way in which ever direction shuts down the fuel you want the fuel screw screwed in so the engine has no fuel then count 3 turns to open the screw to give it about 3 turns of fuel each carb same way one after the other)

Stattz in your case after you do this take out the spark plug keep them in order and see which one is wet or fuel fouled or dry as a bone. they may all be dry now if you havent tried to start the bike in a few days


spin engine to get loaded fuel cylinder dry.

Stattz check points make sure they are gaped and havent moved or closed
a too small a gap will give very weak spark.a too large agap will do the same< get them about 015 .and clean with emery board or fine sand paper.get them shiny.

only after this is done ! turn all screws in three full turns (MAKE SURE THEY HAVE TOUCHED THE PAD OF METAL THEY MAKE CONTACT WITH BEFORE COUNTING)

When you have multiple carbs its best to take tank off so you have a clear veiw of what your doing(this is important) as its important to watch them make contact then to start counting.

rest tank on bike dont mount as it will come off again for adjustment .

make sure points are clean and gaped make sure plugs are clean and dry put plugs and points cover, back on bike .

try starting it should start and run fast walla it starts now you have to fine tune unscrew air screws back them out 1 1/2 turns each

start up again see if it seems to smoke or smell fuel means too much fuel unscrew fuel screws 1 1/2 turns.

so you have the idea that the carbs DO NOT run differrent from each other they are all linked to each other and require the same amount of fuel and air.All four carbs need screws turned in or out exact same amount (period)

When you twist the throttle it opens all carbs 2 or 3 or 4 carbs all open at same time, the engine just grabs what it needs when it needsit

again nothing for you to think about its engineered in for you!

just besure to turn them ALL in the same amount and ALL out the same amount

again do not miss the two or three steps checking points even if you checked them before tuning carbs, or if you never looked in there you NEED TO DO Before continuing, IT could be affecting its running and can stop it from running ruff or running at all its KEY To check points before EVER LOOKING at carb tuning .PERIOD

be sure to take out and clean PLUGS and too spin engine with out plugs in it to clear cylinder of unburnt fuel build up (get it dry again)

then adjust all screws evenly...all screws EVENLY .DO NOT THINK THEY WORK SEPARATE FROM EACH OTHER THEY ARE LINKED TO EACH OTHER and need all screws to be evenly adjusted.

you cannot turn one screw more then another BESURE OF THIS

do them all the same all the time and you will have a smooth running bike.

remember its not the carbs ..its ussually weak ignition(closed or opened point gap or valve wear or sticking that will cause ruff running a few tanks with mystry oil will help sticking valves or a adjustment or a gap check to be sure they are not to loose or too tight is also where you look for a ruff running engine.

Carbs are last to look at BUT I TELL YOU EVERY ONE WILL SCREW around with them FIRST dont be one of these peolpe its not the carbs ussually they dont go out of tune and I stand by that statement.

They ussually always are out of tune because some one monkeyed with them instead of looking at points and valves and spark plugs and ignition FIRST!!

they just take patience to get every thing even once your happy with its running its good to put a dollup of paint on the thread so it doesnt vibrate loose like the factory does thats what that little yellow paint is for.ussually they will rust in postition ...I always free mine get them working and adjusted then lock them with a drop of paint yellow is cool like model paint .keep a laguer yellow just for this from a hobby or model shop hell walmart has it in the toy department.

another detail tip to smoth running is get a oil can with mistry oil and get ever twisting turning part afew drops and work the throtle to get every thing free and lubed its these little details that make a smooth running bike .

like the tinman let it sit out side and it will start to get squeeky rusty and it will hang up or freese up and stick when you dont want it to .OIL IT and make sure all moving parts are free .
 

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thats more or less what i was saying. duh. what can screw things up is clogged jets and things like that. if the idle jet is clogged, then he'll have a problem getting it to run right. if theres an air passage clogged, it wont run right. but definitely look at everything else first. chances are, it was running fine when it was parked, or it had a dead battery or flat tires or god knows what else. whatever it was, it probably wasnt the carbs. ive found once they are set, they really dont need messing with.

jc
 

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to stazz's credit the bike came with the carbs in a box and completely disassembled. He's just trying to undo what the previous owner did. eerybody is saying that stock is the baseline and I agree, if you can put the carbs back to the factory settings and start from there you should be able to get a good solid starting point. after that if it leaks fuel adjust the float height, if it runs high, adjust the idle screw and air bleed.

the things that need to be set to stock:
needle height (adjusted in the slide.
float height
air bleed (fuel) screws
Idle screw (on the linkage)

and the slide height adjustments need to be close to the same.

When the bike swings from one extreme to the other, there is usually more than one problem going on. For instance when you first had it running @ 4000 rpm it may not have been the carbs at all but air leaks in the manifold (did you check the rubber intakes for cracks? are they hard or soft?). This is the point in the bike where you really need to check everything carefully. if you can get it running again I usually spray the motor with soapy water (not in the carbs but definatly on top of the manifold) while running and check for air leaks. if the soap bubbles up you have an air leak.

BTW, I hope you changed the oil and filters befor your last startup. starting a single cam with year old oil in it isn't healthy. Most of the single cams I find in storage actually have no oil in them. Your cb550 has an internal oil tank (it's shared tranny motor oil) so make sure you have enough.
 

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Actually, I am the idiot who messed with the carb linkages.

Where is the fuel screw located. My manual says nothing about a fuel screw (other than the throttle stop screw). And the carbs are not identical to the diagrams, which is a bit confusing.

How should I go about undoing the damage I caused by messing with the linkages while trying to adjust the slide? I used the adjuster screw on the top of the link arms (Is this the "fuel screw"). Can I somehow duplicate the factory settings or will that require balancing?
If I adjust the screw, the slide moves up and down, as do the slides in the other carbs. What's going on there?

I'll check the points, plugs etc. as well, then see what I can do.



Stattz
 

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can you post a pic of your carb rack so we can see what is going on.

the air bleed screw (fuel screw) should be on the side of each carb body near the opening. On older carbs it used to adjust the amount of air bleeding in the idle circuit (hence the name air bleed screw) but newer carbs (1969+) it actually adjusts the fuel flow at idle. There are some honda carbs where they didn't have individual fuel screws but a nob beterrn #2 and #3 carb at the bottom of the rack.
 

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Discussion Starter #12
Stattz ...is this helping or are you holding your head from exploding?
George
 

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I posted some pictures of the carbs here

http://home.triad.rr.com/stattz/

This is the first time I've posted pics, so I hope it works!

The screws I messed with are under the top covers.
I'm guessing that the screw between carbs 2 & 3 is the fuel screw, complete with factory yellow paint. The screw located on each the side of each carb must be the air screw, it's in about the same place as in the manual.

How can I return the screws I messed up to stock settings, or should I try to do it a different way, such as balancing the carbs. Can I follow the steps Lil Bull outlined? Closing the (now located?) fuel and air screws, backing them out and away you go: or do they need to be balanced and synchronised?

Stattz

Edited by - stattz on Nov 23 2005 12:44:19 PM
 

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Stattz, do you have a repair manual for this bike? I know this might be a silly question, but I really think most of the answers to your questions are "in the book".
I wouldn't proceed without one.


FR
 

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I have a Clymer and a Haynes. I don't doubt the answers are "in the book", It's knowing where to look and having experience with similar systems that make it a bit easier to interpret what the manual is saying. Esp. since some of the photo's do not match what is mounted on my bike.

Stattz
 

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IIRC there are 4 or 5 different carb types for the cb550 from 1974 to 1978. One is for the 1974, then 1975-1976 and then 2 or three different ones for 1977-1978. The 1974 and 1975-76 are similar with subtle differences, but are way different than the 77-78 different carb types.

The manual covers only two different carb types the 1975-76 and one of the 1977-78 carbs. It is possible that they carb the books covers is different than what he has on the bike, however really all that changes between the different 77-78 models is the location of certain adjustment screws and linkages.

This is why I recommended posting this at SOHC4.us since there will be guys there intimatley familar with these specific carbs.

I know of the carbs you have stattz but the only time I had a bike with them I shitcanned them and replaced them with the 75-76 carbs which make more power and are way easier to work on.
 

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Discussion Starter #18
Stattz I havent worked on that set up of carb but if you sent them to me Id be happy to look them over and set them up for you .Think about it or call me.
My out line works with all carbs its best to have all at a base setting so by turning them all closed then open each the same amount three turns (THATs on complete 360 twist of screw driver will always get you in the ball park to start.

The linkage,the idea is, you want every thing closed at same time back off or turn in all screws that rest against linkage.
be sure everything is inline and all carbs are doing the same thing(all carbs are closed)then lock down linkage and check the movement . besure they all open same time and close same time.

Again its a matter of getting my face in there and I can look and figure it out.

those are very good pictures but they dont help as Id have to watch things move to see whats going on!
So the best I can do is offer to set them up for you call me if you think that route .Ill look at them and adjust them and send them back .

Dont let the terms balancing and synchronizing throw you its the same exact thing initially as make sure every thing is open and closed at the same time.backing in and out the screw evenly is the first form of "Balancing and synchonizing"

And Stattz it truely sucks to work on carbs with those massive air boxes thank good for Cafinating I cut mine out carefully with a saws-all and thru it in the trash now carb work isnt a kick in the balls every time I want to check things out.....



Edited by - LiLBull on Nov 23 2005 4:38:34 PM

Edited by - LiLBull on Nov 23 2005 4:41:17 PM
 

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I posted it for you and here is the response so far:

http://www.sohc4.us/forums/index.php?topic=5608.0

quote: Yeah he has a mess there. As you said those carbs arent covered in the Clymers. Maybe he can get ahold of an actual Honda shop manual for the 78. The screws he messed with under the top cover are for syncing the carbs. He seems to be under the impression that there are two screws for air/fuel mixture. As you know there is one screw per carb and in his case they meter fuel. They are the screws under the carbs, in front and center of the float bowls(toward the engine) and they are mounted vertically. If he bottoms them out clockwise then turns them out 1.5 to 2 turns, that should be a good base point. He'll need to pull the carbs again and try to bench sync them(sorry I dont know the specs for the slides) then sync them while its running. He should be able to measure the clearance on the cut away side of the #2 carb and match the others to it. The #2 carb is the "preset" carb and is the one that you match the others to durring a sync. Match carb 1 to 2, then 4 to the others and finally 3. He'll probably end up having to increase the vacuum on 1 and 4 a bit once he does a running sync since their inlets are longer. I think the screws he mentions having the yellow torque paint on them are for adjusting choke but Im not certain. All said, he should probably find a set of carbs that havnt been pulled off the bank or messed with, and use those as a reference. Nothing wrong with having extra carbs and parts right?
 

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I read the replies onthe SOHC forum. Looks like its time to pull those carbs again. Thanksgiving first. Then we'll see.

Thanks for all the help, it truly is appreciated.



Stattz
 
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