Topic: 1977 Honda CB550K

[MgMt CB550K]

I am beginning to work on a '77 Honda CB550K which has only 4,700 miles on it.  However since it has such little milage it has obviously been sitting around for probably 10 years.  I started by taking the carburetors apart and draining the gas can.

The carbs had a lot of gunk that I removed with a lot of carb cleaner, scrubbing with a toothbrush, and a flat head screwdriver where it was necessary.  I am planning on borrowing a Carburetors sync tool from a friend but I am not sure where to hook it up or what the correct setting should be.  Does any one know about this about this?

Also my list of things to do on this bike is as follows:
- Clean/Tune carbs
- Flush gas tank
- Replace front/rear wheel bearings
- change oil
- change oil filter
- new tires/tubes

Am I missing anything that i should be doing?  I would like to get this bike into operating condition before the cold weather sets in and then once the winter comes I can get into the nity gritty details.

[TwoTired]

Probably should do a hydraulic overhaul to the front brake.

Not sure why you want the wheel bearing replaced, they are sealed, and with only 4700 miles, shouldn't be worn out.  The bearing retainers are staked and can be a real pain in the anatomy to get free.

Flushing the tank may not be enough.  If there is rust, this needs to be removed.
Lube the clutch and throttle cables.

New battery, I presume?

Check the fuse clips for oxidation.  It is sometimes transparent.  But, it must be cleaned off anyway.  Resistance heating can melt the fuses without an over current.

The slow jets of the carbs are pressed in.  Pull them straight out and clean for light passage.  Then tap back in after cleaning the passage behind them.

Cheers,

[mmtsquid]

I have the same bike, with almost the same mileage (although it goes up daily!) - listen to whatever TwoTired tells you - He's forgotten more about these bikes than I'll ever know!

The synch is improtant - but to get going, simply do a "bench synch".

With the carb bank off of the bike, adjust the idle screw so that a .125 drill bit will just fit between the throttle valve and the air intake on carb #2 (from the left).  This carb has NO adjustment, all others will be synched to match this one.
Now, go to carb #1, and try to put the drill bit in the same place.  If it fits perfectly (and it might, unless you have COMPLETELY dismantled the carbs), then its good, move on to the next one (#3, #4).

If it is loose or tight, then take the "top" off of the offending carb, loosen the locknut, and adjust the screw until the bit fits perfectly, tighten the locknut, and move on to the next one.

If done correctly, this will get you very close, and doesn't take very long.

Happy riding, bro!

[ieism]

Here's some other stuff to make it a complete tune-up:


Adjust tappets (with cold engine)
Check the points gap and timing
Adjust/check Camchain
Clean and gap your sparkplugs (or buy new ones)
Brakes, you'll probably want to rebuild the front...
Airfilter, check , clean or replace.
Drivechain, chainslack and lube.
Before syncing the carbs, make sure they are clean. Clean the tank and fuellines too. In fact: Sync the carbs after you've done everything else on the engine.

Syncing carbs is really easy, borrow the tool (vacuumgauges)from your friend and give it a try:

Don't let the engine get too hot when syncing it, let it cool down when you get one carb good or get a fan or something to cool it.

1. Remove the tank, and hook up a temporary fuelbottle. (You can also try doing it with the fuel that's just in the lines and carbs, but you'll have to be pretty quick)

2. Remove the screws from the vacuum holes. There is one on each inlet manifold (between carb and engine) Put a small amount of grease on the tip off your srewdriver to prevent the vacuumscrews from falling down and getting lost.

3. Screw in the extenders from the vacuumgauges by hand, don't screw these in supertight or you won't get them out. They ussually have rubberrings , so just make sure they are on AIRTIGHT.

4. Connect the tubes, keep them in the right order with your meters , from cylinder 1-4.

5. Start the engine, and adjust tickover to 1050 RPM.

6. Blip the trottle a few times and let it return to idle, now look at the gauges. Are all 4 reading the same ?

7. The object of sycing is to get them all as close as possible, don't worrie what the meter read as long as you get them equal.

8. (on certain models 550 and 500, the nr. 2 carb can't be adjusted. If this is the case you try to get all the other gauges to read the same as nr. 2.)

9. There is a sync-screw with a locknut for each carb, they are located between carb 1&2 and 3&4 and can be seen/adjusted from the top (that's why we had to take the tank off). Get a pipewrench that fits the locknut, and a screwdriver that's long enough to go through the pipewrench to reach the screw. Also put an adjustable wrench or something on the upper end of the pipewrench so you can fasten/loosen it gently while still holding the screw in position with the screwdriver.

10. Loosen the locknuts. Now simply turn the screws a little at a time, untill the meter are all equal(or close to it as you can get them) Blip the trottle every now and then between fiddling the screws. Don't worry if the gauges are not all dead on, a small variation is no problem.

11. when you're done, fasten the locknuts while holding the screws firmly in place so they don't move out of sync again. Put vacuumscres back in, adjust the idle to normal and put the tank back on. Done!

Hope it works....If I forgot something, please fill in guys..

[MgMt CB550K]

Unfortunately TwoTired was correct about there being some rust in my gas can.  I was draining it yesterday and the gas had a rust color to it and I could see some rust when looking down into the gas can.  Also the fuel petcock doesn't seem to want to drain the fuel from the tank unless it is on reserve.

Most importantly does anyone know how to remove rust from a gas tank???

Also should I just buy a new fuel petcock or try to fix the one I have?  It seems to be riveted together so I think buying a new one might be easier...

[OldSchool_IsCool]

Rust Removal & Treatment:
- search the forum, there is a TON on knowledge here on that very topic!  Believe it or not, molassis is a fairly common rust remover.  Al sorts of commercial tank coatings after that.

Petcock
- riveted and unserviceable.  Fear not as the problem could likely be a plugged internal fuel strainer.  Take the petcock off.  then, gently pull out what looks like a nylon washer.  Be careful tho, cuz that washer is actually a sock that the petcock tube slips into.  Clean or replace the strainer then try to blow out any crap that might be in your petcock with compressed air or a few shots of penetrating oil.  If you still can't get good air flow thru the petcock after a few tries, then you may well need to replace it.

[MgMt CB550K]

I searched the forum on removing the rust from my gas tank and found a really good looking solution but at the same time an expensive one.  So yesterday when I was in the autoparts store getting some oil and starting fluid and asked the owner what he thinks I should do about rust in my tank.  He told me that Muriatic Acid is commonly used to strip rust out of gas tanks.  He told me that if the rust seems to be light surface rust that I can probably slush the Muriatic Acid around in the tank and that should take the rust out without having to recoat the inside of my tank.  Has anyone ever heard anything about that??

Besides the tank I cleaned the carbs last week and got them onto the bike the other night and had the battery changing overnight until yesterday when I got out of work.  I was curious to see if the bike would start so I could see what kind of adjustments the carburetors need. 

I had to make a gas can out of some tubing and a water bottle since the tank has rust in it. When trying to start the bike I determined that the carbs were still clogged up somewhere and were not taking in the gas and getting it to the cylinder.  I determinded this because the only times is would start is when it breathed in starting fluid.  So it seems that I have to take the carburetors back off.  I am suspecting that the fuel rail is clogged up which is preventing the gas from entering the carbs, does this sound about right??

One of my friends said that soaking the carbs in concentrated simple green and the blasting them clean with compressed air and carb cleaner.  Does this sound like a good idea?? 

On a positive note I was happy to see that the starter, headlights, the tiny little horn, and brake lights worked.  The blinkers look like they need a little work but I am thinking it is just a bad relay.

[OldSchool_IsCool]

You can test your fuel rail with the carbs on by cracking open the float bowl drains and catching the fuel in a container.  Try this with each carb individually and make sure it passes more fuel then the bowl itself would normally hold. 

You mentioned that you have already cleaned the carbs, but for future reference, inspection of the first few drops of bowl liquids can often give you a picture of what is going on in there without having to remove them.

Slow or stalled flashing can be weak battery, insufficient output of your stator due to engine at idle (you may note better flashing upon reeving the engine) or corroded connections in your wiring.  Take some time to shine up any and all electrical connections and pack them with dielectric grease to slow the corrosion process

[mmtsquid]

Brother, I feel your pain - my carbs gave me fits for a LONG TIME!!!!!!!!
Simple green is great stuff - use it!
At this point I'm going to assume you've removed the jets, and can in fact see daylight through them.
With the jets in place, get a can of carb cleaner and blow through them - if all is well, you should see a corresponding stream of carb cleaner squirt into the intake - if not, you've got more work to do.......

Compressed air is your friend - you can't hurt anything by blowing through all of the passageways.
If that isn't getting rid of the gunk, try a small guitar string.  They are very flexable, and do a pretty good job of forcing out crud, but be gentle - you don't want to scratch things up inside there (scratches can alter fuel flow, causing weird things to happen).

[MgMt CB550K]

OldSchool_IsCool:
Slow or stalled flashing can be weak battery, insufficient output of your stator due to engine at idle (you may note better flashing upon reeving the engine) or corroded connections in your wiring.

The battery that is in the bike is brand new so I am assuming that it is pretty strong.  The right hand blinker turns on and stays on but the rear bulb does not go on.  I am thinking that maybe the bulb and burnt out so this might be stopping the blinker from working.

The left hand blinker started off blinking and then stop blinking and stayed on.  When it was blinking there was a beeping noise each time it would blink.  Is this something that is built in to start beepings after the blinker has been on for an extended period of time?

OldSchool_IsCool:
You can test your fuel rail with the carbs on by cracking open the float bowl drains and catching the fuel in a container.  Try this with each carb individually and make sure it passes more fuel then the bowl itself would normally hold.

I did open the drain at the bottom of the bowl and nothing came out.  This has got to mean that gas isn't even entering the carb.  I am curious to see if there is anything in the carb when I take it apart.

[TwoTired]

The beeper works in concert with the signal flash rate.  I like to keep it working so I remember to turn them off.  There are many who believe that it interferes with the loud pipe sound and disconnect it.  As the attention they attract is not "cool".  Apparently it IS cool to drive miles and miles with the blinker flashing steadily.

The flash rate is voltage and load sensitive.  When the battery falls a bit with voltage drain, the flash rate slows or stops.  Reving the engine restores battery voltage and flash rate.  I use this on my bikes as a battery condition indicator.   Also, the stock bulbs (1034/ 1078) are often PO replaced with higher wattage bulbs 1157/1156?  This also effects the flash rate function.

If this is a problem for you, a three terminal electronic flasher can be purchased that will blink regardless of system voltage level.

Cheers,

[MgMt CB550K]

I stripped the carbs down last night furher than I had before.  When I took them apart I didn't see anything that screamed the answer for the carbs not getting any fuel.  the fuel rail seemed to allow fluid and air through it but maybe something broke free when I blew some air through it.  When I took the bowls off the carburetors they were all dry except for the number 2 carb which had a little bit of gas it in.  So there is no way the gas was making it to the others.

One thing that I did notice was that it seemed like the main jet (I think it's the main jet.  It's the flat head that you can adjust on the bottom front of the carb right next to the bowl) was screwed in all the way on a couple of the carbs.  I'm not sure what effect this would have on gas or air flow through the carburetor.

Either way the carbs are soaking in some simple green and I am hoping once I clean them all up and put them back together that gas will start to distribute through the carbs.

Has anyone ever used Muriatic Acid to remove rust from a gas tank?

[bryanj]

The MAIN jets are INSIDe the float bowl and need to be screwed in tight (yes the 77/78 has threaded jets)
The adjusters outside the floatbowls going straight up are the idle mixture adjuster and need to be set as manual
ALSO inside the floatbowl are the idle jets which are push in type NOT screw in type but can, and need to be, removed and cleaned.

No matter what you soalk them in it wont clean them enough withought removal and an air line

[TwoTired]

One thing that I did notice was that it seemed like the main jet (I think it's the main jet.  It's the flat head that you can adjust on the bottom front of the carb right next to the bowl) was screwed in all the way on a couple of the carbs.  I'm not sure what effect this would have on gas or air flow through the carburetor.

Listen to Bryanj. 
To elaborate:
 The adjustable part is the Idle Mixture Screw.  It is adjusted by turning it out from LIGHTLY seated 1 and 1/2 turns.  The pointy end has a very shallow taper.  If screwed in too tight, it jams in place and the tip breaks off during extraction   This leaves the cylinder with no fuel below 1/8 throttle position.

The slow jet in side the float bowl has a very small hole (orifice) about 0.015 inch in diameter for fuel passage.  If things aren't squeaky clean inside, these plug up and stop fuel flow.  As above, no fuel to the cylinders below 1/8 Throttle position.  Pull them out and clean them.

In both cases above, application of choke will force extra fuel from the main jet so you may only operate the engine above about 3000 RPM.  Without choke, it will likely stop running.


Cheers,

[MgMt CB550K]

Alright,
So Thanks for all the advice on my carburetor issues.  It took me a little while cause I had some things come and and I was also getting fairly frustrated so I would just go cool off and think all the problems through.  Which by the way is how I solved my problem.  If you guys remember I was having issues getting gas into the bowls of the carburetors and therefore into the cylinders.  So after screwing with the carbs and some gas I realized an embarrassing truth.  I put the floats back on upside down!!!  It sucks but I guess the only silver lining is that I cleaned the heck out of those carbs and I got pretty comfortable with them.  So once I got them all back together the CORRECT way the bike started right up...  She even idles. 

So the next couple things on my list are as follows...

The front wheel does not roll very well at all.  So I am going to start by taking the front brake caliper off and see if the pistons are seized in the out position pushing against the disc.  If that is the case I'm not sure where to start with that since I have never taken anything like that apart.  Is it even possible and what should I look for?

Once I get the front wheel rolling free I need to remove some light rust from the inside of my gas tank as well as unclog or purchase a new fuel petcock.  For the rust I am thinking of getting some Muriatic Acid.  The owner of the auto parts store told me to go get some a the local hardware store and use that in the tank.  Has anyone ever delt with this stuff or know how long I should keep it in there?

Oh yeah and my Tachometer isn't working either so I am hoping that the cable is just seized.  Any thoughts on that?

[OldSchool_IsCool]

Glad to hear you got your carbs sorted out!  when it comes to the '77 and '78 carbs, the only reliable manual is the Honda service manual.  Claymers and Hayes apparently didn't get the memo about the drastic difference in those years.

Caliper:
Read the brake FAQ here on the site.  You can get to it via the pull-down list at the bottom of this page.

Muriatic Acid Tank Wash:
Search the forum for success and failure stories on tank cleaning.  there are a lot out there, many using muriatic acid.

Tach Cable:
Make sure it's tightly screwed into the back of the clock and also bolted down tight on the valve cover.  If it is, then pull it out of the valve cover and inspect the gear teeth.  If they are chewed up, replace the cable.  If they look good, then unscrew and inspect the clock end.  If both look good, wrap some tape over the gear teeth and stick it in the chuck of a drill.  Lightly tighten then use the drill to see if the clock end spins too.  Attach it back to the tach.  Can you cause needle movement with the drill (very slowly until you know which direction it goes)?  Report your results here for widely contradictory steps on what to do next.

[MgMt CB550K]

I did some more work on the bike last night making some progress.  My Buddy came down with a mercury sync and we synced up the carbs in about 10 minutes (with the right tool it was really easy).  While doing this though gas started to come out of an overflow tube which seemed to be from the airbox chamber (where the carbs hook up to the airbox).  I am thinking that maybe a value that is hooked up to the float is getting stuck and not closing.  Any other ideas?  Also could this gas also be going the other way into my cylinders???

Another issue that I discovered last night was that cylinder #1 was backfiring.  It wasn't;t doing it allot but it would happen every once and a while and then it would happen if I rolled on the throttle.  What would be causing this?  Misfiring? Timing? To much gas from the flooding carb???

[OldSchool_IsCool]

Fuel Overflow:
Yes, likely that the float valve on at least one of your carbs is not closing due to incorrect adjustment or debris in the valve seat.  Rust in the tank?  Likely debris.  Lightly tap each bowl with the handle of a screwdriver in hopes of knocking any crud loose.  May need to drain the bowls first (screw on bottom of bowl) then tap as you refill them.  If it still overflows, then it's time to pull the carbs for cleaning and adjustment.  Here is where you will need the Honda shop manual as Haynes and Claymers manuals ignore the drastic differences with the '77 & '78 550 carbs.  So, don't put that sync tool away just yet!  Another issue is that overflow should flow out of the overflow tubes on the bottom of your float bowls.  Check them for blockage.

Backfire:
Did you adjust your tappets earlier in this process?  Does your #1 header pipe heat up just like the other three?  Backfire is due to too much "burnable" fuel making it into a hot exhaust pipe.  May be a tappet out of adjustment, may be a carb set too rich.  May be any of several other possibilities, including a misbehaving float.

[MgMt CB550K]

So I am taking a little break from working on the carburetors and trying to get my front break free.  While doing this the bleeder value snapped off.  I drilled out the center of the valve but still could not get it to come out.  I went to the hardware store and got a screw extractor but I drilled out the valve so that the extractor hits the bottom before it can grad the walls of the screw. 

I am thinking my next move is to drill out the valve completely as well as the threads in the hole and tap some new threads.  I'm hoping that this will work but I am concerned that I an not going to get all of the valve out since I don't know what it looks like inside the caliper.  Is it designed so that it is possible to drill out the entire valve or am I going to leave part of it down there?  I have been carefull so far to try and reduce the amount of metal flakes getting into it...  Any suggestions?

[Da Nurze]

Hey ,

All of you!  I was trying to decide whether to buy this beautiful old, very old, 1977 CB550K with 22,000 miles on it. Well after reading all the help and what seemed actual fun from you guys, I bought it. I will attach a pic soon. So far no problems but I feel comfort knowing you are all out there..........


Da Nurze

[Gordon]

Hey ,

All of you!  I was trying to decide whether to buy this beautiful old, very old, 1977 CB550K with 22,000 miles on it. Well after reading all the help and what seemed actual fun from you guys, I bought it. I will attach a pic soon. So far no problems but I feel comfort knowing you are all out there..........


Da Nurze

Glad to hear it!  You won't regret it (most of the time)

[OldSchool_IsCool]

Welcome to the club, Da Nurze!

Here is a list I put together a while ago for those new to stock SOHC/4 bikes in general and 550's specifically.  Hope you're still happy with your decision after reading this!!

- the brakes suck, don't ride past your ability to stop
- don't let fuel leaks go unattended, especially above the engine (don't ask how I know    )
- pull the plug caps off the plug wires.  If there is any green in there, shine up the spike in the cap and trim the wire back to clean copper.  Don't cut too short tho!!
- Double check that you have the right plugs.  Your caps have resistance, your plugs shouldn't.
- 15-amp fuses --- don't leave home without some!
- a bad fuse can "look" good.  If you suspect it, replace it.
- The 550 has a habit of "melting" it's fuses under the cap where you can't see it.  If this happens to you, search the forum for the solution
- watch your tire pressure close
- you have a "wet" sump and "wet" clutch (i.e motor oil rests in the bottom of your engine and is supposed to be in the clutch)
- oil level is measured with the dip stick set in the hole, not screwed down
- Chain lube that doesn't fling off the chain and onto your pants hasn't been invented yet
- Old School is COOL! (heard that somewhere)
- exhaust megaphones are WAY over priced!
- SeaFoam (gas addative) is awesome! (pause while those that disagree roll their eyes)
- death, taxes, and SOHC/4 oil leaks
- OEM gaskets are the only way to go (yes, Honda still has them)
- for better battery charging, run your engine at or above 3000 RPM
- HondaMan and TwoTired are God's!  Glad to have them as members here as well as the rest of the clan!
- The moderators are way under appreciated!
- Crotch rockets hurt my back just looking at them
- downshift, throttle, bubye!
- Cagers (vehicles with 4 or more wheels) are not to be trusted
- A helmet and a leather jacket are instant cool!
- Any distraction (radio, iPod, cell phone, beautiful girl) can mean death on these machines.
- Only a motorcyclist knows why a dog loves to stick it's head out a car window
- forget about wheelies, front or back
- High side, low side, super man --- I'd rather avoid the crash all together.  (your safety class will explain this)
- the rear wheel adjustment notches aren't accurate.  Measure from rim to swing arm on both sides to align the rear wheel
- don't expect three-digit milage.  These bikes weren't built for fuel efficiency.  Anything above 40 is great!
- the speedometer will read about 5 MPH over your actual speed
- wiring, especially the connectors, need TLC.  Spend a day shining and packing them with dielectric grease
- don't let moisture get into your points!! if the gasket is bad, a little high-temp grease will get you back on the road while you wait for or make a replacement.
- if you have the under-seat tool kit, don't leave it on the shop bench when you ride!
- if you don't have an under-seat tool kit, get one or assemble one of your own
- keep the greasy side down and the leathery side up!
- no matter how long you have ridden, you are never fully prepared
- know your limits and the limits of your machine, respect them both!
- reasonable engine breaking (downshifting) is not going to hurt anything.  With as bad as these brakes are, practice it.
- practice panic stops too!  May save your life some day
- your front brake is 80% of your braking power
- don't take your bike to the auto wash if you plan to ride it home (again, don't ask how I know!   )
- a novice rider is a dangerous thing, so is a novice mechanic.  Doubly so when they are the SAME person!  I know this because that describes me!  Hook up with an old timer mechanic, someone who has actually HEARD of points!  Let them give your bike the once over twice so that all those subtle yet deadly things you and I might miss will get caught.
- You can park almost anywhere
- If you pack them in carefully, you can get 6 bikes in the garage space where your car used to be   
- you almost never walk away from your car - backwards.
- Nobody wishes they were you when you ride in your car
- We are a community, with our own language, and we wave at each other when we pass by
- Oh, the conversations you will get into when some old-timer walk up as says "I used to ride one of those!"
- Getting lost on your bike only means you get to ride more
- Car drivers never say "Man, I'm really ON today!"
- A motorcycle is it's own roller-coaster, any YOU control the thrills
- the whiskey is for contemplative and celebratory times, not for ride'n or wrench'n times
- the painted lines and figures on the road are very slippery when wet.  Don't stop on top of any if you want to keep your paint in good shape.

[blackhog02]

MgMt CB550K,

the 77 CB50 is a great bike.  Don't get frustrated with those carb you will get them dialed in.   I am not exactly running stock on my 77 cb550k. I had to move the clip on the needle and had to take the carbs completley apart. Man was that fun.  then when I put them back on gas came out the pod filter.  Float was too high, then the gaskets started leaking,  had to order the po boy kit.  It was finally worth it in the long run.  Bike runs great and I ride it almost daily. 

Started as the blue bike now is the red bike
http://www.mptrackclub.com/Photos/cb750f/75cb750f.htm

[ieism]

- your front brake is 80% of your braking power

Slight correction:
On a normal bike the front is 80% and the rearbrake 20% of your stopping power.

On a 550: The front is 40% of your stopping power, and the rearbrake 10%. The air drag and the rolling resistance from your tires 5%, Engine braking another 5% if you happen to be in the right gear.
The remaining 40% will probably be a car, a tree, or a pole in front of you.

I always keep a fairly long distance in front of me, so I have enough space for just the air drag to bring me to a stop.

[OldSchool_IsCool]