Topic: Carbs and plugs and gas, oh my! (not running...again)**update** Running!

[Sprocket75]

At some point and time, I really hope to actually ride this machine, rather than just performing surgery on it. I mean, you guys do actually get to ride them once in a while, right?     Right?  Guys?

Ok, so on to the new issue. Last night, I connected my gauges, see photos, and started her up. In the first photo, you'll see that the needles were all over the place, especially cylinder #1. By the way, I connected the gauges in the order of the cylinders from left to right. (so, 1 2 3 4) And just so I won't get scolded, this is a 1975 Honda CB550K... Back to the issue, the gauges were all over the place, so I began slowly adjusting the screws on each carb, which were all at the same starting point as per the manual. (1.5 turns out) I started with the #4 carb and worked my way down. After some adjusting, I was able to balance out the carbs 4, 3 and 2 fairly close. (see second photo) As I started to adjust carb #1, the bike began to die. The needle never would get anywhere near to the same point as the other three gauges. If I backed the screw out, the bike would rev waaaay up. If I closed the screw, the bike would start to cough and clunk and sputter and try to die. So, I decided to start over and try to match the other carb screws to the #1 carb. I backed the #1 screw out about 2 turns, and started to adjust the other carbs, making sure to blip the throttle a little. Well, to get anywhere close on the needles, I had to back #2, #3, and #4 screws Waaaay out to even get close. By now, the bike was idling all over the place but high. Way too high. So, I decided to once again, start over. I reset the screws back to factory specs again, pressed the start button, and now she wont start. She wants to start...she told me. She tries to start. But no success. So, I took the plugs out to check there first. (see photos) As you can see, they were fouled. I cleaned them, checked the gap, and reinstalled. I also installed an inline spark tester. Spark is VERY strong. I then checked the timing and cleaned the points. Timing is dead on. Next I checked the bowls. Each had about the same amount of fuel (or close to it) as measured in my high tech baby food jar with sharpie marker marks. (say that three times fast!) 

I have a hot wife. No really, she's pretty hot. I think she wants to ride as much as I do. I really want to take my hot wife out on this machine. Hot wife is starting to question my abilities...in the garage. So, A=hot wife B=CB550 C=time unable to ride D=desire to ride
With this information, we can then deduce that:  (A+B)*D > C in theory. However, this equation is not accurate and reflects: (B+C)-A=D

Can someone help me with this equation?

[Bodi]

What screws are you adjusting?

[Sprocket75]

Each carb has a screw on the linkage. It has a locknut and center screw. I am not sure what the "technical" name is for it, but here they are in the photo.

[flybox1]

(assuming your sync gauge is calibrated and reading correct)  it might be best to set all those screws the same(without the gauges on), and then bench sync your carbs before you jump into vacuum syncing.
you're running out of adjustment range with those vacuum screws, and you need to reset the adjustment range to a good baseline. followed by a good bench sync.

IIWM, id pull the carbs and do the above before anything else

[Sprocket75]

Yeah, I planned to take them off again and bench sync them...again. Just wanted to see if anyone had any additional opinions.

[Nidhoggr]

*raises hand* Am I gonna be the one to ask when the pictures of Hot Wife are going to be posted?  Those are totally relevant to your math question!  Can't find the solution without them! 

[Ewan 500K1]

so I began slowly adjusting the screws on each carb, which were all at the same starting point as per the manual. (1.5 turns out)  If I closed the screw, the bike would start to cough and clunk and sputter and try to die. So, I decided to start over and try to match the other carb screws to the #1 carb. I backed the #1 screw out about 2 turns,  I reset the screws back to factory specs again

I have a hot wife. No really, she's pretty hot. I think she wants to ride as much as I do. I really want to take my hot wife out on this machine. Hot wife is starting to question my abilities...in the garage. So, A=hot wife B=CB550 C=time unable to ride D=desire to ride
With this information, we can then deduce that:  (A+B)*D > C in theory. However, this equation is not accurate and reflects: (B+C)-A=D

Can someone help me with this equation?

I've never seen any manual specify settings for the slide adjusting screws.,, ie the ones in your photo with the locknuts.  The one and a half turns out generally refers to the pilot mixture screws.  Bench syching the carbs before using your gauges shpould help you to get to a good starting point... that gets them to roughly the right place for follow on fine tuning with the gauges. Plenty posts on the forum about bench synching

For the euation.  ...... put up a photo of A to encourage more participation by forum members in your quest, which should ensure rectification,  then (A+B)/D = infinity and C is out of the question

[Sprocket75]

*raises hand* Am I gonna be the one to ask when the pictures of Hot Wife are going to be posted?  Those are totally relevant to your math question!  Can't find the solution without them!

ROFLOL! 

[oldschoolcarbs]

Those things can be a real bear to zero out once they're way out of whack. The reason being that beyond a certain critical point, turning one carb's synch adjuster moves the slide on the others and NOT the one you're turning.

You'll want to have them off and adjust them so that 1) every slide is bottomed out, AND 2) when you turn the main idle adjust screw they ALL begin to rise at EXACTLY the same time and by 3) EXACTLY the same increment.

Once you're there you can proceed to on-bike (engine running) synch, but if your compression is roughly equal you may find (if you've done the process properly) that you're plug and play.

We do a lot of these carbs and I don't own a 550, which is to say that the lack of complaints on them being out of synch on arrival suggests that we're hitting it right, but they do indeed take more time to bench synch than even the CBX'es.

While you're doing it on the bench, continually move the idle adjust back and forth by half-turns and operate the slides to ensure that they're all in unison and staying there.

OSC
http://www.oldschoolcarbs.com

[Sprocket75]

Thanks for the info and suggestions! I am going to take them off again tonight and re-bench sync them. I obviously was not accurate. I've read several posts on this forum that use the "drill bit" method to sync the carbs...as well as ball bearings...flashlights...potato chips...etc. (okay, I made up the potato chip part) I used a drill bit to sync mine when I had them on the bench last weekend. I am guessing there is a more accurate (orthodox) way to do this?

[flybox1]

well, the Buddhist way to do it is pretty simple. 
if your #2 carb is the slave carb,  grab any drill bit, and raise all you slides with the idle adjustment (set) screw.
raise them just so that your bit slides into #2 and under its slide.  lower all the slides using the idle adjuster screw so it pinches the bit and 'feel' any resistance as you gently pull the bit out.  you wont need to adjust the idle screw until you are done.
now match that resistance 'feel' on #1, 3, & 4, but adjust these individual slides by their top linkages. 
once all 'feel' the same, lower all slides with the idle set screw to ensure they all drop completely closed.
Now, go in sync, Grasshopper! 

[GoldWingWiz]

Not Sure If ONE of your 4 Carbs has an accelerator Pump (like the # 3 one does on my GoldWing).....But if there is one look there as part of your diagnostic process. 

I am finding that ethanol in gas and rust in Vintage gas tanks (and YES it does get by ALL Fuel Filters) can mess up those little seals, springs and air valves that Mother Honda just loved to put in all the bikes of that era! 

Good Luck!

[Sprocket75]

well, the Buddhist way to do it is pretty simple. 
if your #2 carb is the slave carb,  grab any drill bit, and raise all you slides with the idle adjustment (set) screw.
raise them just so that your bit slides into #2 and under its slide.  lower all the slides using the idle adjuster screw so it pinches the bit and 'feel' any resistance as you gently pull the bit out.  you wont need to adjust the idle screw until you are done.
now match that resistance 'feel' on #1, 3, & 4, but adjust these individual slides by their top linkages. 
once all 'feel' the same, lower all slides with the idle set screw to ensure they all drop completely closed.
Now, go in sync, Grasshopper! 

Dear Yoda,
I am trying to adjust the air fuel atomizer devices on my light speeder. I need you to show me what the "idle adjustment (set) screw is. My speeder bike has 4 screws on the linkage on top near the larger brass bolts. Are these correct? Or, are they the smaller screws near the lower part of the air fuel atomizers that are attached to the "choke butterflies"? I tried using my light saber for illumination, but wound up melting the seat in the cockpit. I gotta go, R2D2 is drunk on WD-40 and is draining his oil on Chewbacca.
Jedi in training,
Luke

[flybox1]

should be near 3/4 carbs, between the carb and engine.  large finger screw with pizza slice lines cut in the knurled top.

check this thread, too...
http://forums.sohc4.net/index.php?topic=110114.0

 "Now, witness the power of this fully operational battle station CB550 " 

[iron_worker]

If your plugs fouled just from idling that long then your idle mixture must be off.

Does your bike have a stock airbox and exhaust? Do you know what jets are in it right now or what the idle mixture screws are set at?

IW

[Sprocket75]

Everything is stock except for the exhaust which the previous owner changed to 2 into 1 on each side. The jets are whatever comes stock on a 75 CB550K I assume. I haven't changed them, just cleaned everything. When you say "what are the idle mixture screws set at?"...are you referring to the screws on the upper part of the carbs, lower part of the carbs or the "pizza slice" cut screw? So many people call all of these things by so many different names. See photos I posted? The screws in the RED circle? Or the screws in the GREEN box? Thanks.

[Ewan 500K1]

Part Diagram might help ? .. attached

The Idle Mixture Set Screw (one on each carb) is part 7 in the attached digram

The Idle Adjustment screw, the BIG one with knurled knob at the end of the carb rack's spindle is part 10 in the attcahed parts diagram

... none of which are shown in your red/green box pics

The  screw in your red box pic is simply a screw that keeps all the choke flaps linked so that they all open / close togeather when you put the choke lever up/down

Your green box pic shows two individual slide adjustment screws and their locknut as part of the individual carb top linkages. You can adjust these with a spanner and screwdriver ... but the jobs much easier , quicker and simpler with one of these:

http://www.carbtune.co.uk/carbtool.html

responses must be worth a pic of Hot Wife (otherwise known as variable A) by now ?

[Vinhead1957]

I have a lot of problem with the vacuum on cylinder 1.  You have 0 vacuum = bad valve adjustment or bad o ring in your intake or bad valve.   They all should replaced while you have the carbs off.   You are running very rich.  Does or did the bike run well with choke off?  Did you also do a compression check?

[Duanob]

No slave carbs, master carbs, or accell. pumps on these carbs.

it is a science and an art to get these synced. Adjusting one carb will affect vacuum in the other ones. it takes pots of patience. Flybox is correct about getting them close by a good bench sync first. Never mind the "factory" setting of the adjustment screws, some will be way off. As long as you don't run out of adjustment it is fine. Yes to the Idle knob screw adjusted as far out so the carbs are closing all the way before you start syncing. Make sure your idle is low as well. the lower the better. I try and sync them at 1000 RPMS eventhough my bike idles at 1200 - 1400. Are you sure you plugged any and all air leaks? All floats are set the same? All needle clip positions are the same?

[Sprocket75]

Ewan: I have that exact Carbtool.     (still debating of wife pics...this is a public forum.  )  Thanks for the diagram! Man, that makes a huge difference. I did not pull those screws out (#7) when I cleaned the carbs...to be honest, I was unaware of them .    But now that I know, I will certainly be pulling them out for a good cleaning. Thanks!

Vin: The bike ran with the choke off. To fill you in, the bike ran previously, and there were no issues with cylinder #1 before I pulled the carbs to clean. I ran a compression test on all four last week and they all showed 150psi across all four. (actually, the true reading would be more like 160 or 170 if you adjust for the gauge tube volume, fittings etc.) But to answer your question, yes, I did perform a compression test. Now, I could very possibly have a vacuum leak somewhere on that carb boot. Since I am going to remove the carbs again, I will certainly check that. Thanks!  **On a side note, I removed the battery and airbox to remove the carbs. Is it possible to do this without removing the battery and airbox?

Duanob: It is VERY possible that I do have an air leak on the #1 boot. The others seem to behave/react like normal. So, I will check that tonight when I remove the carbs again. The floats are set the same, I was pretty meticulous about it, but then again, I am human and do make a ton of mistakes...so it is possible that they are less than 1/5465th off?    Yep, needle clips are all the same in the exact same position they were in when I removed them. I put them back exactly like they were. So, apparently, I am bench syncing them wrong. I think? or my floats are off... I think?   **The crazy thing is that when I first started her last night, she sounded really solid. Throttle response was smooth and crisp, revs were nice and clean etc. She hung a little coming down, but I just assumed I could work that out during syncing. Of course she was on the stand with no load on her, but still makes me scratch my head. I obviously threw her waaaaay out of whack.

What are the RED and GREEN arrows pointing to in this photo?

[Ewan 500K1]

still debating of wife pics...this is a public forum.  ) 

  It was you that mentioned her  . Who are you debating with, the wife  . If dont put one up now we'll think either a)  she's not A at all but some monster with four heads and 3 arms or b) she's a figment of .....

Thanks for the diagram! Man, that makes a huge difference. I did not pull those screws out (#7) when I cleaned the carbs...to be honest, I was unaware of them .    But now that I know, I will certainly be pulling them out for a good cleaning. Thanks!

Its these screws that the manulas say should be out one and a half turns as standard

This link is great for diagrams, just plug in your model number. If you know a part number it can also show you a list of all the models that share that part

What are the RED and GREEN arrows pointing to in this photo?

RED = needle (connected to the slide) fitting into main jet... comes upwards & out the main jet as you twist the throttle open

GREEN = air intake for pilot circuit 

Here's a good FAQ thread
http://forums.sohc4.net/index.php?topic=5410.0

" Honda Motorcycle Carburetion, 1975" is good tome on Honda carbs. Sure its on here somewhere, but cannae find it just now. See page 12 if you can find it

[Ewan 500K1]

forgot to stick the link on for the parts diagrams:

http://www.motogrid.com/p/OEM-Parts

Also, good carb FAQ here:

http://forums.sohc4.net/index.php?topic=5410.0

[Duanob]

Duanob: It is VERY possible that I do have an air leak on the #1 boot. The others seem to behave/react like normal.

remember the o-rings that go between the intakes and head. if you've never changed them i would recommend it. After 35+ years they get old, dry, crack, split, and shrink, etc.

[Sprocket75]

Duanob: It is VERY possible that I do have an air leak on the #1 boot. The others seem to behave/react like normal.

remember the o-rings that go between the intakes and head. if you've never changed them i would recommend it. After 35+ years they get old, dry, crack, split, and shrink, etc.

I am 35+ years...and I get dry, crack, split and shrink etc. too.       Lol.
Have not had time in the last 24hrs to even step foot in my garage. Grrrrr.... Work work work work.

[Sprocket75]

Finally got back in town and was able to work on the bike today. I removed the carbs again, and disassembled the linkage etc. Starting from scratch, I performed a complete bench sync on the carbs. I used the drill bit technique and also tried the light technique using a super bright LED. Got all of the slides in sync, reassembled the linkage and put the carbs back on. Gas...check....battery...check....key...on... Once again she came to life! ...and this time...ALL 4 CYLINDERS! Man what a sound. This is honestly the best she has EVER sounded. Clean crisp revs, no lag... The vacuum gauges all read identical and they all behave identically! I can honestly say that there is no substitute for a really accurate bench sync. Makes all the difference in the world. She purrrrs like a kitten at idle. The bench sync helped so much in fact, I barely had to adjust the slides at all. Needless to say I am thrilled! Could not have done this without everyone's help... THANK YOU! Now, if the rain holds off, I am going to try to actually put this machine on the pavement tomorrow.