Topic: My first bike (77 CB550K) and all the joys that come with it.......

[mmtsquid]

Hello all!
I've been reading this forum for several weeks now, and have found TONS of useful information (enough to allow a noob to tackle the carbs).
Many thanks to everyone for taking the time to post all of this knowledge!

I'm starting this thread to post my problems and keep from doing something stupid........

First question - After cleaning the carbs and reassembling, the bike runs, but has no top end (will barely hit 75 MPH).  Any ideas?

Second question - It rides ROUGH!  Should I drain the fork oil and start over?

Any help would be appreciated!

PS  Pics to come soon - as soon as I figure out how!

[jalfonso]

Welcome squid.

I think more information is needed.  Did you just buy the bike and was it in poor condition when purchased or is this a bike you've owned and are now starting to spruce it up. 

You've cleaned and reassembled the carbs with no appearant fuel leaks, which is always a good sign.  Have you synced the carbs?  Keep in mind I am a noob myself and these are just some ideas from my limited pool of knowledge.  There are MUCH more knowledgeable people than me that can help.

The fork oil could be very old or low.  It definitely won't hurt to clean out the forks and put in fresh oil.  You may want to consider progressive springs while you have everything apart.  I don't know what your bank account looks like so I'll leave that one up to you. Depending on the miles the bike has on it you may want to consider replacing the swingarm bushings.  Hondaman can get your swing arm dialed in.

Just my $.02. Hope it helps.

[greenjeans]

I'm pretty much a noob myself..... but I have put new seals & oil in the forks, along with a good cleaning.... it's a pretty easy & inexpensive job.   Only takes a couple of hours or less...  There are manuals that you can download on this site that show pics etc..    There is one little trick to get the bolt out of the bottom of the fork tube (after you get things broken down a bit) and that is to put a wooden handle from a plunger or similar in there and clamp it with a bar clamp - it puts enough pressure on the inside to let you loosen it.... there's a pic here: http://www.sohc4.us/forums/index.php?topic=19789.15 that kinda shows what I'm talking about.

You can download a Honda shop manual for the CB500/550 here : http://www.cryscom.nb.ca/Documents.htm

Have fun, welcome to the club

[Tvag]

Nice to see someone else on the forum working on my bike. I'm a noob to and have been working on my '77 550K for 6 months now. Mine is in pieces as I have to literally clean every square inch as it sat for 20 years. I've got a thread for my bike in here you can find using a keyword search for rusty '77. I've done the carbs, rear wheel, front brake, pipes so far and the rear assembly in peices at the moment. I'll be watching your thread to see if I can help at all. Good luck getting her in ship shape.

Can't help you with the '75 miles per hour problem but if you haven't synched your carbs yet that would be a good place to start so I hear.

[mmtsquid]

I just purchased the bike - 2800 original miles, $700.  Bike has been repainted, and over all was in fine shape - just nasty carbs (bike had not moved in two years).
It's currently getting new tires (why fool around with old rubber?).
There are a lot of unknowns at this point, but as I get more info I will post updates!

[bryanj]

Try a full engine service to get the power also the 77/78 carbs are awkward ones that can look clean but aint

[mmtsquid]

OK, after cleaning the carbs AGAIN (idle jets were gummed up), bike runs VERY strong, but cylinder 2 isn't firing at idle speed.  Getting spark, has compression, must not be getting gas....

Also, bike tends to backfire and pop while going down the road.......have to search the threads for that symptom as well......

How do I get pics small enough to upload?

[Gordon]

OK, after cleaning the carbs AGAIN (idle jets were gummed up), bike runs VERY strong, but cylinder 2 isn't firing at idle speed.  Getting spark, has compression, must not be getting gas....

Also, bike tends to backfire and pop while going down the road.......have to search the threads for that symptom as well......

How do I get pics small enough to upload?

Sounds like the idle circuit on carb #2 is still clogged.  You can clean the jets all you want, but if the passages in the carbs still have anything in them, it won't run right.  Spray carb cleaner in all the carb body passages and then blow them out with compressed air.

As for pictures, either reduce them to <80 KB or get a free photobucket account and post them from there with no size restrictions.

[OldSchool_IsCool]

How do I get pics small enough to upload?

My photo editing software let me save the file in "best for the web" size.  Seems to work pretty well.

[mmtsquid]

OK, pics will be posted tomorrow.
My short ride yesterday revealed a few things........
1.  The suspension STINKS!  The bike rides like a log truck......
2.  I don't really care for the seat.  Are there any aftermarket options that won't cost $500?
3.  This bike is MUCH faster than I ever anticipated it would be.  Is a 750 that much faster?

[mmtsquid]

OK, as promised, here are the pics.........




Not bad for $700!!!!!!!!!
But the purple stuff has to GO!
Carbs will come off (again) tonight, and I'll see if I can clear up the idle circuit on #2

[xtalon]

But the purple stuff has to GO!

Okay, but if it doesn't, we are going to change your screenname to Prince or Barney.   

Actually in a couple of the pics, I kind of like the purple.  The luggage rack is a bit much though.

Good luck w/ the carbs!

--xTalon

[mmtsquid]

Yeah, I'm not sure what the PO was thinking when he did that......
As far as the luggage rack goes, it might be handy at times, but it is really ugly!  Maybe I'll repaint it and just put it on if I'm going to take a weekend trip.
All of the other purple stuff will come off tonight.

BTW, the rear brake pedal has purple paint on it as well - whats the best way to remove it? (I don't have a sandblaster)

[xtalon]

Yeah, I'm not sure what the PO was thinking when he did that......
As far as the luggage rack goes, it might be handy at times, but it is really ugly!  Maybe I'll repaint it and just put it on if I'm going to take a weekend trip.
All of the other purple stuff will come off tonight.

BTW, the rear brake pedal has purple paint on it as well - whats the best way to remove it? (I don't have a sandblaster)

Lots of people here rave about aircraft stripper, although I've personally never used the stuff.  I've just heard never get it on you!

If there is chrome under that paint, I don't know what aircraft stripper will do to it.  Others here may.  If you have concerns, you may want to go with something weaker.

--xTalon

[Klerk Kant]

you could leave the brake pedal purple as a reminder and a warning.
-KK

[neil young]

when i bought my 1977 cb 550 last year i couldnt get above 70 mph on the highway.after i adjusted the tappets,points and cam chain , put in new plugs and did the timing i can get her up to 90 to 95 mph.i just installed some ngk wire connectors to the stock coils,new 7mm wire and new ngk resistor caps and a dyna s ignition and she is running like a top.i havnt tried to top 100mph yet but maybe this weekend .from what i have read these bikes did about 110 mph brand new

[mmtsquid]

Ah, success..............
Sure enough, #2 idle circuit was clogged - the jet was kosher, but the passageway into the "body" was clogged - a bit of air took care of things.
Adjusted the mix screws to 1.5 turns out, and reassembled.
Voila!  Runs MUCH better - but I'm still not happy with how it idles - still seems a bit rough when I try to get it to idle at 1050-1100 (what I've read it should idle at).
It behaves much nicer at 1400-1500, so I'm not really sure if I should leave well enough alone, or attempt additional surgery.
Also, still getting some "popping" sometimes while running down the road at constant RPM (4-5K).
I noticed something else last night - with bike idling in neutral, and clutch engaged, I hear a little noise.  Pull in the clutch, it goes away.  let it out, and rev to 2K RPM, and the noise seems to go away as well.
What gives?

[OldSchool_IsCool]

I'm not sure about the clutch noise, but the idle is possibly a carb sync issue.  Did you bench sync them last time they were off?  Did you dynamically balance them once back on?

[mmtsquid]

I did bench sync, or rather bench check, as no adjustment had to be made.
What do you mean by dynamically balance?

[OldSchool_IsCool]

Using a manometer to compare the relative vacuum pressures at the intake manifold (between carbs and motor).  The actual value of the vacuum is not so important, but the relative "pull" of each cylinder is.  They should all be reasonably the same. 

This procedure is typically the last step performed during a tune-up (after tappet adjustment, point gap, timing, etc).  You also want to do this if you have had the carbs apart.  Look for the specifics of the procedure in your shop manual or search this site.

[mmtsquid]

Yeah, I don't have a manometer - guess I'll need to buy one.

[OldSchool_IsCool]

I think Z1 has a manometer (4 vacuum gauges + tubing, not sure if it has has the vacuum port nipples) for around $50.  There are some urban ledgens of homemade meters on this site (I'm working on one myself!)

[mmtsquid]

Well, as I keep riding the bike, things keep improving!
It feels a little better every day.
But one thing does keep happening - if I'm cruising slow in first (like through the neighborhood) and then give the throttle a good twist, it hesitates for a second, the lurches.  What is this a symptom of?

[OldSchool_IsCool]

That behaviour is oft called a "stumble" and is generally thought to be a result of the sudden change of the fuel-air ratio when the throttle is opened radically.  Some carbs deal with this problem with an accelerator pump that dumps fuel into the larger air stream.

Search the site for "stumble" and you are sure to get some ideas on how to deal with it as your carbs don't have an accelerator pump.

My bike had a stumble problem last month and I tried a previously unmentioned fix.  I don't have conclusive evidence yet that indeed the stumble was cured by what I did.  I'm going to reverse my fix this month and see if the stumble returns and then re-apply the fix to see if it goes away.  If it does, then I will at least have convinced myself that it works.  More on that later ... maybe.

[dusterdude]

if your carbs have an accelerator pump,then you probably have pump issues,if you dont then thats why it stumbles.