Topic: New guy, need a lot of help.

[Ace2cool]

All right, so I bought a CB550 a few days ago, and it's about a wreck. Came with no air filter, baffles chopped out of the mufflers, and unbalanced stock-ish carbs. I've got a balance kit on order, so there's that, but I've got more problems than just that, and I've never worked on a carburetor before, much less 4 at once.

SO, here's where I'm at. The previous owner cleaned and "rebuilt" the carbs, which basically entailed OEM sized jets, and looking at and soaking everything. I called him today and apparently he didn't put new needles or seals in. I'm sure it doesn't help that the extent of my carburetor knowledge is how to set the mixture, and I'm very basically proficient at that. So here's the symptoms, followed by a video:

Doesn't want to keep an idle unless the idle screw is set way in, have to mess with the choke sometimes just to keep it running after it's warm, sputters under load, is sluggish up until about 2k rpm, then gets power all of a sudden, sometimes backfires (mainly through carburetor while under load,) backfires while revving, both through the exhaust and cabruretors (mainly the #1 carb,) won't go over 4-5K rpm. Also has white smoke from left exhaust pipe.

Those were the symptoms yesterday, this morning, I went and cranked it, then put some gas in it, and as I was filling it, gas started pouring out of the carburetors. WTF? I quickly shut off the fuel at the tank, then let the idle screw all the way out. Washed the bike off, rocked the throttle, then hooked the gas tank back up and turned the fuel on, then gas started leaking out of the #2 carburetor drain line only. Turned gas off, rocked the throttle a couple of times, turned the gas back on, and same result. I have no idea what I'm doing with carburetors, and any help you guys may be able to provide will be greatly appreciated. Lastly, here's a video of start, idle, rev, exhaust sound, and a quick run up to 3rd gear down the street, and back. I apologize for the 2nd half of the video, as it's hard to pin a cell phone under your chin and ride a motorcycle at the same time. The 2nd half is mainly for the sound while under load, though.


Well, I would post a video, but the forums won't let me. I can't post an outbound link and the forum won't allow an MP4 as an attachment. I have the video on my flickr account though, which is aaronparris. It'll be the first file on the profile. I would convert the video to upload it, but I'm not on my own laptop, and I'm not gonna download stuff to a company computer. My PC is back in CA.

[tlbranth]

Ace - your symptoms are really irrelevant at this point. You need to start at the beginning, clean, set and check all the carb stuff. Fix sticking floats, balance carbs, set points, replace plugs, time ignition and blah blah blah. There won't be a magic bullet that makes it all run right. Odds are there are several things need attention and you should just go through the systems one at a time. It isn't all that hard but you'll need patience. Look through the FAQ and PROVEN TIPS sections and you can learn how to do all you need to fix the bike up. A shop manual would be a big plus. Hondaman's book would probably be another. Read stuff and ask questions when in doubt or when you get stuck. Good luck.

[Ace2cool]

Well, the good news is, I'm not a total failure so far. I've got the float bowls disassembled, and everything seems to be in check there, albeit very dirty for having just been rebuilt and cleaned. Sludge in the bottom of the bowls, dirt caked on the floats, and most of the leaf springs were installed backwards from the way they're supposed to be keyed.

Thanks, I didn't know there was an FAQ section yet. I guess I broke my own pet peeve of any forum: posting without looking around and searching the site I'm already on. 

[Ace2cool]

But just for the record, it does seem more like a carburetor issue, correct? With the "mods" (i'm going to be getting small foam filters instead of the stock box and the mufflers being gutted,) will the stock jets be fine, or am I just going to have to tear the carbs down again and replace everything all over again?

[Stev-o]

Welcome. First rule: dont ever believe what the seller tells you!

Yes, check out the FAQ section, very good info. Good luck.

[Dimitri13]

What year is it? What model carbs are they?

First step is do do a complete 3000 mile tune-up. Oil/filter, points, timing, valves, all that jazz. Actually, the FIRST first step is to get a haynes or clymer manual, and the shop manual which can be found at the top of the SOHC4 Bikes forum. In the manuals, it'll tell you in what order to do everything.

[Ace2cool]

It's a '74 CB550, and the only markings I can find on the carbs, other than the manufacturer mark says "022A"

I've been stuck in the FSM for the past 2 days, but I feel dumber after reading it, lmao. It's talking like I already know where all the parts are. I'm in progress on the carburetor 101 in the FAQ.

Welcome. First rule: dont ever believe what the seller tells you!

Ok, I'm not surprised by any of this, but if you're gonna give me a bike that obviously has carb issues, and then tell me the carbs were just cleaned, come on man. *rolls eyes*

I mean, it does look like the jets and needles are brand new, but I haven't checked float clearance or anything like that yet. I need some carb cleaner. I started a little late on this project, and let the store close before I thought about.

[BeSeeingYou]

Clean the tank.  All the carb cleaning and setting up will do no good if you have junk in the tank.  The stock setup with the carbs will not work properly with pods and "gutted" mufflers.  If you insist on this setup be prepared for a lot of trial and error in jetting and needle position.  Or save yourself the trouble and track down an airbox...it will run better.  Leaking carbs are caused by sticking floats or junk on the float needle seat.  Sounds like the idle jets are also plugged. 

[Dimitri13]

Definitely 100% tear into those carbs.

Some points to remember:

1. Remove the emulsion tube. It's the tube that sits underneath the main jet. It can be tapped out gently from the top; be sure not to put any marks in it. Clean it thoroughly. You may want to read HondaMan's tips (can be found in the Tech Guide on the main site) about the emulsion tube.

2. Replace the needles. The taper may have changed over time. The stock clip position is the 4th notch from the top (top being the part that's closer to the top of the carbs when oriented as if it were on the bike).

3. Replace all the jets, float needles and seats, jet needles, and o-rings. Stock jet sizes are 38 slows and 100 mains. The pilot screw stock setting is 1.5 turns out from fully seated. Screwing it in/clockwise will enrich the pilot mixture, out/counter clockwise will lean the pilot mixture. This is only for final tuning.

4. Blow out all the passages thoroughly with compressed air, or at the very least, the pressure from a can of carb cleaner with the nozzle tube. Buy two of the big cans of carb cleaner, for safe measure. You can soak everything in simple green (an ultrasonic cleaner would be awesome), but not too long, or it'll discolor the bodies. I've heard some members have boiled in simple green with good results.

5. The float height is 22mm. If you only have an SAE dial caliper like me, the setting is .866". Be sure to check both sides of the float.

6. Bench sync the carbs (search around on the forum for the procedure), and make sure you sync the carbs after they're installed. This is VERY important.

7. Check very carefully, using a magnifying glass or vacuum tester if possible, for cracked overflow tubes.

8. The float bowl o-rings will likely be just a hair too small. You can use superglue (just a tiny drop will do) or petroleum jelly (I haven't had much success with it) to keep them in place. DO NOT pinch any gaskets. They will cause hazardous leaks and can damage the float bowl threads in the carb body (ask me how I know). The screws must be tightened evenly or you risk damaging the body threads. What I like to do is hold down the bowl so there's NO pressure against the screws.

9. Patience and attention to detail is a MUST.

10. When running fuel through them for the first time, it's very likely they'll piss fuel. This can be prevented by tapping the bowls with the handle of a screw driver while it's filling up. I'm still not really sure why it does it, but even after a thorough clean, it'll do it to me. An alternative is starting the bike while it's filling up, that usually prevents it for me.

As for my recommendations on your intake/exhaust setup, I'd highly recommend using the stock airbox. Track one down if you have to. Pods, or even stacks, are more trouble than they're worth, and will almost always provide less-than-satisfactory results (poor throttle response off idle, mainly). Some members would recommend using pipes with baffles, and I'm one of them. Not only do they provide the backpressure our engines need, but overly loud exhaust is just obnoxious and detrimental to the riding community.

And like I said before, perform the 3000 mile tune-up. I'd also recommend checking, and most likely replacing, the plug wires and caps, points/condensers (you can get a new set from PartsUnlimited whick distrubutes to nearly every reputable bike shop, part number 2105-0067).

If you have any more questions don't hesitate to ask the forum or even PM me.

[harisuluv]

Welcome!  As you can see the forum is a place full of people willing to help you!  Glad to see you are already getting into those carbs!  If you get stuck or have any questions you can call me and I will help you out.  Number is in my sig!  Good luck!

[Dimitri13]

Oh, almost forgot. I'd recommend replacing all the float bowl screws with SS allen head bolts. They look so much better and make it easier to access the jets without pulling the carbs. At a chain hardware store that sells individual screws, it'll probably cost you around $8-10 for a set. They're M4x10 (I think they're 10, double check your screws). Standard thread pitch, which I think is .7

[Ace2cool]

Definitely 100% tear into those carbs.

Some points to remember:

1. Remove the emulsion tube. It's the tube that sits underneath the main jet. It can be tapped out gently from the top; be sure not to put any marks in it. Clean it thoroughly. You may want to read HondaMan's tips (can be found in the Tech Guide on the main site) about the emulsion tube.

Does the tube have to be removed to clean it, or can I do it while I have the slide valve out and just spray some cleaning compound through it?

2. Replace the needles. The taper may have changed over time. The stock clip position is the 4th notch from the top (top being the part that's closer to the top of the carbs when oriented as if it were on the bike).

After looking at the needles, I'm almost positive these are the new ones and the mechanic just put the old ones back in the bag, and that confused the previous owner. They're also set 4th notch from the top, so we'll see what happens after I thoroughly clean them here in an hour or so.

3. Replace all the jets, float needles and seats, jet needles, and o-rings. Stock jet sizes are 38 slows and 100 mains. The pilot screw stock setting is 1.5 turns out from fully seated. Screwing it in/clockwise will enrich the pilot mixture, out/counter clockwise will lean the pilot mixture. This is only for final tuning.

Good info on the pilot screw. Thanks loads.All the internal hardware is brand new.

4. Blow out all the passages thoroughly with compressed air, or at the very least, the pressure from a can of carb cleaner with the nozzle tube. Buy two of the big cans of carb cleaner, for safe measure. You can soak everything in simple green (an ultrasonic cleaner would be awesome), but not too long, or it'll discolor the bodies. I've heard some members have boiled in simple green with good results.

This is definitely going to be a must, because previous owner put seafoam through the tank, and it all ended up in the carbs.

5. The float height is 22mm. If you only have an SAE dial caliper like me, the setting is .866". Be sure to check both sides of the float.

I found that in the Service manual, but the part about the float valve arm confused me. Do you let the floats hang down like you're checking them, and then make sure the arm is barely touching the tip of the float valve? If so, that's probably why mine flooded on me, since none of them were even remotely close. And all my floats are currently 23mm, uniformly, both sides of the float. How would that affect the bike? I'm going to pick up a caliper when I go get carb cleaner, but this is just curiosity. I'm one of those curious minds who likes to understand the how's and why's, lol.

6. Bench sync the carbs (search around on the forum for the procedure), and make sure you sync the carbs after they're installed. This is VERY important.

I read a procedure about using a 1/8" drill bit. Is that the recommended procedure, or is there a better way?

7. Check very carefully, using a magnifying glass or vacuum tester if possible, for cracked overflow tubes.

Seeing as these just hang back behind the carbs, what is the purpose of making sure there are no cracks? I've already bought all new vacuum tubing, but this has piqued my interest.

8. The float bowl o-rings will likely be just a hair too small. You can use superglue (just a tiny drop will do) or petroleum jelly (I haven't had much success with it) to keep them in place. DO NOT pinch any gaskets. They will cause hazardous leaks and can damage the float bowl threads in the carb body (ask me how I know). The screws must be tightened evenly or you risk damaging the body threads. What I like to do is hold down the bowl so there's NO pressure against the screws.

More good info here, thanks for that, and also about the allen key head bolts in your next post. I'll definitely be doing that.

9. Patience and attention to detail is a MUST.

So I've seen. Working on a 40 year old piece of equipment is going to have its trying times, but if I can work on my Nissans, I should be OK here, lol.

10. When running fuel through them for the first time, it's very likely they'll piss fuel. This can be prevented by tapping the bowls with the handle of a screw driver while it's filling up. I'm still not really sure why it does it, but even after a thorough clean, it'll do it to me. An alternative is starting the bike while it's filling up, that usually prevents it for me.

As for my recommendations on your intake/exhaust setup, I'd highly recommend using the stock airbox. Track one down if you have to. Pods, or even stacks, are more trouble than they're worth, and will almost always provide less-than-satisfactory results (poor throttle response off idle, mainly). Some members would recommend using pipes with baffles, and I'm one of them. Not only do they provide the backpressure our engines need, but overly loud exhaust is just obnoxious and detrimental to the riding community.

I was planning on heading to the salvage yard today, so I guess I'll pull one of those as well. I've got the front half of it, but not the part where the filter actually goes.

And like I said before, perform the 3000 mile tune-up. I'd also recommend checking, and most likely replacing, the plug wires and caps, points/condensers (you can get a new set from PartsUnlimited whick distrubutes to nearly every reputable bike shop, part number 2105-0067).

If you have any more questions don't hesitate to ask the forum or even PM me.

TONS of good info, just in my first day. I had no idea this forum was going to be this active! I already love it over here!

[Ausmithe]

You definitely need to remove the emulsion tube to ensure it is clean, no two ways about it. You'll understand why once you pop it out and see all the tiny holes that get clogged so easily.

The float height is set as you said, where the tab is just making contact with the float pin. If you have your float height too high, it can cause a high idle.

The importance of checking the overflow tube is that a crack can cause your carb to be pissing gas and starving that cylinder of gas. They work by preventing gas from "overflowing" the carbs until it reaches the top of the tube. If you have a crack in that tube, you'll be losing gas in that carb instead of maintaining it at the proper level to feed your cylinder. Cracks in these tubes can be hard to spot so you will need to examine the tubes very closely to ensure they are in good shape. If you find you do have a crack, there are a few good posts on repairing them in this forum.

Good Luck to you! You'll find tons of valuable info here and don't be afraid to tackle something new. Carbs can be intimidating but there is no substitution for knowing that they have been cleaned and setup properly because you did it yourself. It also goes a long way to help you diagnose any future problems you may have because you know exactly how things are set in your carbs, and aren't guessing about what the PO did or didn't do.

[Ace2cool]

You definitely need to remove the emulsion tube to ensure it is clean, no two ways about it. You'll understand why once you pop it out and see all the tiny holes that get clogged so easily.

The float height is set as you said, where the tab is just making contact with the float pin. If you have your float height too high, it can cause a high idle.

The importance of checking the overflow tube is that a crack can cause your carb to be pissing gas and starving that cylinder of gas. They work by preventing gas from "overflowing" the carbs until it reaches the top of the tube. If you have a crack in that tube, you'll be losing gas in that carb instead of maintaining it at the proper level to feed your cylinder. Cracks in these tubes can be hard to spot so you will need to examine the tubes very closely to ensure they are in good shape. If you find you do have a crack, there are a few good posts on repairing them in this forum.

Good Luck to you! You'll find tons of valuable info here and don't be afraid to tackle something new. Carbs can be intimidating but there is no substitution for knowing that they have been cleaned and setup properly because you did it yourself. It also goes a long way to help you diagnose any future problems you may have because you know exactly how things are set in your carbs, and aren't guessing about what the PO did or didn't do.

Ah. very well. It's probably beyond clogged, since it visually looks like a straight pass through under strong light. And I see now we're talking about the actual tube itself, not the hose attached to it. *facepalm* Well, I've got 2 huge cans of B-12 here, so I guess it's showtime!

[Tews19]

Sounds like you are on your way. Do not use carb cleaner on any rubber parts though. Will rot them fast and trash them

[Ace2cool]

All right, I got my caliper, which turns out to be a bit more accurate than the ruler I was using. I can't get these floats to go down past 25mm. Where should I bend them? I got them down to 22, but that was just because I was hitting the bump stop on the connecting link between the floats. No matter what I do, they're right at 25mm every time.

[Ace2cool]

Don't tell me i'm supposed to use that little tab to hold it to 22mm....

[Scott S]

 Yes, you bend the tab. It's sort of counterintuitive.....bend it opposite the way you want the floats to go. I still get nervous because it takes slightly more effort or force than you'd think and I always feel like I'm going to break it or go too far. Try a small, flat blade screwdriver or one of thos pick tools to bend it.

 Also, listen to what these guys said about the 3,000 mile tune-up. You'll never get the carbs right if timing, valve clearance, etc. is off. Do that first, the carbs come last.

[cgswss]

Please, until you get the bike running right, use an air box.  Pods introduce so many problems and make it so hard to find real problems.

Have you got the carbs off the bike or are you trying to work on them while they are still on?

Before you start bending things on the floats, please get the other stuff right .  You need to remove the float needles clean them and work on the needle seats.  I use a q-tip to clean it as best I can.  then I chuck a q-tip in a drill motor and polish the H out of it.

You have to get those jet tube clean and you should sharpen the tip on the straw for the carb cleaner so you can put it into each and every port you can find and blow them out.  If you find some that will not blow out  post your results.

You should "check" the floats/needles before you put everything back together.  Get them about level over something to catch the gas and turn the the gas on.  you should have gas pouring out of all 4 carbs.  you should be able to to push each float up and see it stop the flow.  You may want to do this one carb at a time and have float bowls on the other 3 to reduce the spilled gas.  Or you can find some rubber bands that will hold the floats up on the carbs you aren't testing.  this is not a real good idea, because you could screw up a float real easy.  I'm lucky as I live with my brother in law- who isn't afraid to get gas on his hands and we just hold the floats up  (4 hands-4 carbs)

[Ace2cool]

*facepalm*

I was sitting here trying to precariously balance it and about to pull my hair out, lmao.

I also bought a feeler gauge set, so we'll see how the clearances look. Spark plugs have already been done, and the oil looks new, and the guy said he changed it, but I may do it again just for that warm fuzzy, and not to mention I can't prove it's a new filter. I should have this bike up and going soon though.

I really hope the salvage yard has a 4 to 1 exhaust. That would be awesome. These pipes are obnoxious. Previous owner: "HURR DURR, let's gut the muffler and make it real loud like one of them thar Harlee Davidsuns!" *shakes head*

Air box is a must-have now, based on what you guys have been throwing out. No pods, I promise.

[Teatimetim]

http://youtu.be/NG6QpwYxmYg

This is not the best video for this, and I would separate the carbs.. but its a starting point on learning

[cgswss]

I hope you checked how thin the feeler gauges go.  A lot of the ones you buy in the auto parts only go down to like .008

[Ace2cool]

.....it's like you guys know what I'm doing before I even tell you I'm doing it. This set did actually only go down to .008. I'm gonna have to return it, but right now, I'm half done with these carbs, and they are looking suh-weet.

[Fritz]

Good to see another 550 is saved from being scrapped.

Now that you are at the carbs, make sure that the rubber boots between head and carbs and air filter and carbs are still soft and sealing well. If not, buy new ones. They are available at fleebay.

You might have a hard time to find all the parts that belong to you model's air box:
http://www.cmsnl.com/honda-cb550f-super-sport-550-four-1976-usa_model467/partslist/F++15.html#results

You can make it without parts #19-#22 on the fiche, but than you must route your crank case fumes so that they do not contaminate you rear tire.
You'll want most of the hardware that mounts the air filter box in your frame:
#3, #4, #15-#17, #25,#26, the box #9 and the cover #7 which, if you find one, will come with #11.
#5 is said to be unobtainable, but you can substitute it with some bent wire of a coat hanger, or so.

Finally, here's the warning for everyone who's new to the 500/550: Be careful, if you every plan to remove the valve cover. Read the manual and this thread: http://forums.sohc4.net/index.php?topic=109553.0

Cheers
Carste

[Dimitri13]

You already got a bunch of responses, but I'll respond to most of these anyway.

Definitely 100% tear into those carbs.

Some points to remember:

1. Remove the emulsion tube. It's the tube that sits underneath the main jet. It can be tapped out gently from the top; be sure not to put any marks in it. Clean it thoroughly. You may want to read HondaMan's tips (can be found in the Tech Guide on the main site) about the emulsion tube.

Does the tube have to be removed to clean it, or can I do it while I have the slide valve out and just spray some cleaning compound through it?

http://img.photobucket.com/albums/v337/LesterPiglet/Betty%20Bloos%20Mum/Project%20Betty%20Bloo/DSC03182.jpg

2. Replace the needles. The taper may have changed over time. The stock clip position is the 4th notch from the top (top being the part that's closer to the top of the carbs when oriented as if it were on the bike).

After looking at the needles, I'm almost positive these are the new ones and the mechanic just put the old ones back in the bag, and that confused the previous owner. They're also set 4th notch from the top, so we'll see what happens after I thoroughly clean them here in an hour or so.

If they're new ones, they should be good then. Even the old ones might have been good, but if the carbs were ill-maintained, the taper can start to change.

5. The float height is 22mm. If you only have an SAE dial caliper like me, the setting is .866". Be sure to check both sides of the float.

I found that in the Service manual, but the part about the float valve arm confused me. Do you let the floats hang down like you're checking them, and then make sure the arm is barely touching the tip of the float valve? If so, that's probably why mine flooded on me, since none of them were even remotely close. And all my floats are currently 23mm, uniformly, both sides of the float. How would that affect the bike? I'm going to pick up a caliper when I go get carb cleaner, but this is just curiosity. I'm one of those curious minds who likes to understand the how's and why's, lol.

You must set the float height to 22mm. If not, even a small difference will make a big impact. Increasing the float height would cause it to run lean or even run out of fuel at higher throttle positions. Decreasing the float height will make you run rich or just simply leak fuel. To set the float correctly, you can either hold the carb in one hand, and angle it so that the tang is just barely touching the needle, then checking the height. Another way to do it (which is the way I like to do it), is to hold the carb upside down in one hand, and with your finger, move the float to the proper position. That gives me more control over the float, because I have pretty shaky hands. You're measuring from the bottom of the carb body (where the float bowl gasket comes in contact) to the highest point on the float. That should be 22mm.
Another thing to be aware of is when taking the pin out to release the float, be gentle. The float towers are prone to breaking and can be a pain to fix.

6. Bench sync the carbs (search around on the forum for the procedure), and make sure you sync the carbs after they're installed. This is VERY important.

I read a procedure about using a 1/8" drill bit. Is that the recommended procedure, or is there a better way?

That's a good way to do it. Another procedure people like to do is shining a flashlight through the opening, then adjusting the slide to where the light is just coming through.

7. Check very carefully, using a magnifying glass or vacuum tester if possible, for cracked overflow tubes.

Seeing as these just hang back behind the carbs, what is the purpose of making sure there are no cracks? I've already bought all new vacuum tubing, but this has piqued my interest.

Like someone said, you're checking the brass tube that's on the bowl, not the rubber hoses. These will cause frustrating leaks, or can have the same effect as a float that's set too low (higher number) if the crack is big enough. I had a cracked tube, and I used heat shrink to fix it, and it's still working eight months after. If you're handy with a soldering iron, you can solder the crack. Not with the electrician's solder, but the other kind.

9. Patience and attention to detail is a MUST.

So I've seen. Working on a 40 year old piece of equipment is going to have its trying times, but if I can work on my Nissans, I should be OK here, lol.

What Nissans you have?

10. When running fuel through them for the first time, it's very likely they'll piss fuel. This can be prevented by tapping the bowls with the handle of a screw driver while it's filling up. I'm still not really sure why it does it, but even after a thorough clean, it'll do it to me. An alternative is starting the bike while it's filling up, that usually prevents it for me.

As for my recommendations on your intake/exhaust setup, I'd highly recommend using the stock airbox. Track one down if you have to. Pods, or even stacks, are more trouble than they're worth, and will almost always provide less-than-satisfactory results (poor throttle response off idle, mainly). Some members would recommend using pipes with baffles, and I'm one of them. Not only do they provide the backpressure our engines need, but overly loud exhaust is just obnoxious and detrimental to the riding community.

I was planning on heading to the salvage yard today, so I guess I'll pull one of those as well. I've got the front half of it, but not the part where the filter actually goes.

Be aware that cracks in the carb boots will cause air leaks and make you run lean. If the rubber has turned hard, that can also cause air leaks, but mainly will be a bear to put on. You can get a new set from a few sites (not sure which) for not an outrageous price.