Topic: 1975 CB550 Sat since 1983

[saxamaphone]

Hi guys, I've finally got going properly on getting this bike going.

Here's what I've done so far:

1.  I was looking around for original exhaust replacements but in the end decided to go for Mac 4 into 1s until I find some               good ones for not too much.

2. Checked the points gap and the timing and got them set correctly.  They were pretty much dead on anyway.

3.  De-rusted the inside of the tank.  It took me a few attempts because the rust would come back.  Evaporust twice, then the toilet bowl cleaner method (worked well) but forgot to rinse with water and baking soda so it rusted again quickly.  Finally got it with the toilet bowl method and then some drywall screws for good measure. 

4.  Carbs:  Original carbs with 100 main jet and 38 idle jet.  Cleaned the carbs (a few times ) I would put them back on the bike and start it but it was having issues idling well after it warmed up so I'd take the carbs off again and there'd be tiny flecks of rust in the bowls.  Unfortunately had to do that a few times.  Set the float levels.  Bench synced them as well as I could.  Replaced the petcock fuel filter with a brand new one from the Honda dealership and also the gas cap seal.
They are not vacuum synced yet because I'll have to take it to a shop for that since I don't have the equipment.

5.  Replaced the air intake boots.  Purchased them from a member here and they seem very nice.

6.  Fixed a couple electrical things in the main console.  Still no high beam indicator light however.

7.  The front brake was sticking so I took the caliper apart and cleaned out the grunge in the groove where the seal goes.   Replaced the brake fluid and bled the brake using a speed bleeder that seemed to work pretty well.

8.  I bought tires but have yet to put them on.  Went for the Avon Roadriders. 

9.  There was no air filter when I got the bike so I put in a Uni 4055 stock replacement.  There were a couple pieces missing from the air box assembly.  I'm not sure how that will affect how it runs.  It's the piece in the middle and it's gasket that are missing.  I put some foam overtop of the piece on the right.   

[saxamaphone]

It's running ok as of today but there's a few things I was hoping someone here might be able to help out with. 

It's starts very easily and idles a bit high at first (2k rpm) then comes down and I can get it to idle between 1000 and 1200 rpm with the idle screw.  But it sounds like it surges up a bit when it idles.  Then if a blip the throttle a bit, it will hang pretty high, around 3-5k rpm.  From what I've read here it might be air leak on the intake.  They are brand new boots on the air box side and the engine side ones seem to be in good condition.  I've replaced two of the clamps with #44 clamps that are for plumbing. 

The second issue is some clicking/tapping noises that sound to me like they are coming from the valves.  I don't have a reference for the sound of these engines so I made some videos and hopefully someone with good ears can let me know what they think.

The third thing is some light coloured smoke coming out of the exhaust.  Especially if I rev it.  It seems to go away after letting it run for awhile but it can be pretty intense on the first start up. 

I tried to capture all these things in the videos below.

CB550 Idling 1

The fuel hose routing is not right because I was taking the tank on and off.  If anyone has a good shot of the right way to rout it, I'd be very grateful.  I'm also at a loss as to how the clutch cable should be routed.  I have it coming out to the right of the carbs but it seems a bit crushed under there.

CB550 Idling 2

I've been using an old drum stool to sit and work on it.  It's nice and low.

CB550 Idling 3


   

[saxamaphone]

Forgot to mention the speedo and tach aren't really working.  The tach does nothing for awhile then works until you rev it and then it only goes to about 4k.

The speedo doesn't seem to be working at all.  I will try and take the backs off and see if I can clean and lube things and hopefully that's all they need.

I also forgot to mention that the engine seems to run fairly hot.  Again, I don't have much reference for this but even after riding around the block a couple of times, it's quite hot.

I've also noticed a lack of power when pulling the throttle.  I've tried opening the throttle up and the bike seems to slowly accelerate when I think it should be taking off.

[Tews19]

You need to adjust the valves first, then the cam chain tensioner.. Then sync the carbs... You can hear a little rattle in the engine... Could be out of sync carbs.. But before going any farther, adjust the valves and cam chain then see hwo she sounds... PLease keep the updates coming

[saxamaphone]

Thanks!  That's great advice.  I'll do those in that order and post a new video.

Cheers

[Scott S]

 Do you remember if the pilot jets were genuine Keihin or aftermarket? I had an uncurable hanging idle and it turned out to be the aftermarket pilot jets. Genuine Keihin jets cured it.

 Is the smoke blue-ish//white or black? If it's white, it's oil. Black is fuel.

 +1  on adjusting the valves/cam chain and synching the carbs. Then check for noises.

[saxamaphone]

I'm pretty sure the jets are the original jets.   They seem to be in very good shape. 

The smoke is mostly at start up for the first 5 minutes or so and then seems to mostly go away.  When I rev it, a good blast of smoke will come out again.  That also goes away.  The colour is a whitish blue.  Mostly white.

There's definitely some condensation coming out of the exhaust as I can see it collecting a bit at the end of the pipe. 

I adjusted the valves today.  They were all mostly too tight.  Not by much though.  I couldn't check the #4 exhaust valve because I can't get the tappet cover off.  I've been trying for awhile now and it's not budging.  Pretty frustrating.

I adjusted the cam chain tension using the shop manual and MCRiders instructions here: http://forums.sohc4.net/index.php?topic=76359.msg850826#msg850826. 

I started it up and unfortunately it didn't seem much different.  Then for about a minute the knocking and clicking sounds seemed to quiet down to more of a whirring, but then back to the old way.  I retried adjusting the cam chain tension a few more times but no luck. 

I'm pretty sure you guys are right about the cam chain tension.  When I sit and listen closely to that area of the engine that's where the clacking sounds come from.  The bigger knocking sounds seem to be coming from all over the engine but maybe more towards the valves.  You can feel it in the handlebars. 

The hanging idle still happens if I blip the throttle.  The throttle return spring is good, and I think the throttle cables are adjusted well. 

I decided to check where the new 4-1 exhaust connects with the engine and found a few slightly loose nuts so I tightened those while idling and could've sworn I heard a change in the idle.

This is where I really messed up though.  The far outer right nut tightened to a point and then it suddenly got looser...the bolt that goes into the engine and sticks out for the exhaust flanges to attach to had become stripped a bit along with the bolt that goes on to it.

Sorry for the photo quality.



Anyone know if those bolts are readily available?  They're threaded on both sides with a space in the middle.  Edit:  They are still available from Honda OEM #90044-323-300.

 
 

[saxamaphone]

So I've been starting the bike, listening closely and then re-checking the valves over and over again.  No changes so far.  Still noisy.  If the valves are noisy is that generally because they are gapped to wide? 

The cam chain tensioner is problematic as well.  I've been following the shop manual's instructions but when I loosen the lock nut (when the crank is 15º ATDC) the screw doesn't change position at all.  I'm also able to move the screw about a quarter of the way around.  Is that normal play for the cam tensioner screw?  Also when I turn the screw that little bit, it feels like something clicks inside the tensioner.  It can go back and forth.  I've tried this 15 times and still no change in the noise.  I've also tried changing where the crank is positioned slightly just in case it wasn't quite at 15º.

Any suggestions?  I'm hoping the cam chain tensioner is buggered.

One other thing I noticed is a slight drip of what looks and feels like water coming from where the headers meet the muffler (mac 4-1).  I've tightened the clamp there quite tight so I'm not sure what's going on there.  There's also a black, sooty kind of ring around that same area too that you can wipe off easily.

Anyone have experience with these exhausts?  Any help with any of this is greatly appreciated, especially since I'm not sure how to proceed.

Cheers

[saxamaphone]

Forgot to add that blipping the throttle will still hang the idle high.  No change there yet.  Although it doesn't do that all the time.

[Scott S]

 Have you checked the advance mechanisim? Loose or broken springs on the advancer?

[saxamaphone]

Thanks Scott, no loose or broken spring on the advancer.  I rechecked the points and timing today as well as trying bryanj's way of adjusting the cam chain tensioner. 

The points were well spaced to .014 but the 1-4 ignition was slightly off. 

I was wondering if the test light (for static adjustment) is supposed to come on right when the F mark is lined up?  If so then I've set the timing right for both sides.

The engine still sounds noisy to me though.  The knocking sound and the high pitched clinking sounds are still there. 

Maybe my cam chain tensioner is shot?

Other than those sounds, it starts and idles amazingly well. 

[RAFster122s]

Have you lubed the throttle cables? They are best done off the bike I think but can be done on the bike.
It is possibly that you have reassembled your carbs with something binding but it is more likely to have cables that are binding.
With an old bike you never know if someone before you changed the jets. The stock jets will have the K logo Keihin uses.
Did you replace the Orings on the intake manifold to the head? Leaks there can cause idle issues, doesn't sound like a problem if the idle is getting down around 1k rpm.

The exhaust part you described is called an exhaust manifold stud. It secures the exhaust flange collars with hex nuts.

Tach cable requires lube just like throttle and speedo.

Speedo drive in front wheel rotating when you spin the front wheel? Dissconnecting at speedo end works so you can see the shaft spinning will work also.
Cam chain tensioner couldn't hurt to be replaced, as even not running the parts will age...

[saxamaphone]

Hey RAF, I haven't lubed the throttle cables yet.  By binding do mean something to make them stick when returning?  They are free and smooth.  Even if i manually push them down to make sure they are closed the rev will hang high.

I'll double check to make sure they are original Keihin jets tomorrow.

I didn't replace the O-rings on the intake manifold to the head, but I did replace the boots from the airbox to the carbs.  It's idling really well but has some engine sounds I'm worried about and trying to figure out. Plus the cam chain tensioner doesn't seem to work.  They are pricy to replace.

I'll try your speedo advice tomorrow.

Thanks a lot for the help.  Much appreciated.

[saxamaphone]

When you are checking valves and you have TDC for 1&4, there should be a little bit of movement of the valves on cylinder 1. 

Should there be any sideways movement or strictly up and down?  My valves (or rockers I guess) all have a little bit of sideways movement to them, as well as the tiny up and down movement.

[dave500]

if you dont have slack at this point rotate the engine 360 and have another look,,the t mark means both 1 and 4 pistons are at tdc,,the cam shaft will be at either one or the other on compression,watch the valves move as you rotate the engine,dont just go by those marks,these rockers arent shimmed against sideways movement,there will be some sideways slop.

[saxamaphone]

Finding the TDC where there was slack on the intake and exhaust valves is no problem, I was just concerned that there might be too much movement side to side.  From the sounds of it, they are fine.  I'm trying to figure out the knocking sounds in the engine.  I keep checking the valve clearances and they're set well except for the #4 exhaust valve that I can't get the bloody cap off.  Maybe there's a melted valve under there?  
The valves look to be in good condition, as do the rocker arms.  I've been reading about worn rocker arms and I'm hoping that's not it. 

There is also what sounds like cam chain noise that I've been trying to fix but my cam chain tensioner doesn't seem to be doing it's job. 

I'm going to triple check the points and timing today as well and try the cam chain tensioner a few more times.   

[dave500]

if the carbs arent properly vacuum synced itll sound really rattly almost knocky when idling,itll go away as rpm increases.

[saxamaphone]

Ok, that's great to hear.  I've been waiting to get everything else in order before vacuum syncing the carbs but I guess it doesn't make a difference. 

Cheers

[jason41987]

i was looking through this thread.. and i noticed some guys were quite worried about not having the leaf spring in the carburetor... so? big deal, and pointless to waste your money on a set of carbs off ebay that MIGHT have some springs... do you know how incredibly simple they are to fabricate new springs using some cheap material found in any hardware store?.. so if you get carbs without springs, no biggie, just make some

[saxamaphone]

Luckily the PO found mine but you should make a thread on how to make them and put it in the Tips and Tricks section.  They are hard to find and pricey.

[jason41987]

actually.. i found a thread like that already on here.. guy bent them out of old hacksaw blades and used two drill bits to make the keyhole shape in the center

[saxamaphone]

Hi all, I've been having some trouble since I've been trying to fix the knocking noise in the engine.  I had decided to re-adjust the points and the timing to see if that'd fix it. 

For setting the points gap I used the turning the crank 90º clockwise from the "F" mark then set to 0.014in method.  I also tried just watching until the breaker was at it's widest and then setting it there.

For the timing, I would get cylinders 1-4 close to their "F" mark, turn on the main switch, and slowly move the crank closer to the "F" while checking the blue wire with a multimeter , grounded.  If the multimeter didn't show juice flowing through right when the "F" mark was lined up, I'd move the base until it did.  So right at the point of connection.  Then the same thing with cylinder 2-3.

Since I did this, the bike started once and actually sounded a lot better, much less noise.  Since then however, it won't really start.  It will barely start for a couple seconds then die, even with lot's of throttle.  Before I redid the points and ignition timing, the bike would start instantly no problem, every time (check the video).  I've redone the points and ignition timing a dozen times today and am at a loss.  I must be doing something wrong.

Are the points supposed to spark when making contact?  Mine are doing that right when the meet, and that's also when they show a reading on the multimeter.  I could also see points 1-4 spark a tiny bit when the bike would start briefly.

Anyone recommendations?     

[dave500]

set the gap when they are their widest,then time it with a strobe if you have one,a guy on here used an "E" clip on the main jet groove and a little coil spring to replace the missing leaf spring in those carbs,so easy its an upgrade?

[saxamaphone]

I'm at a bit of a loss these days.  Here's the story.

Bike would start instantly (cold or warm no choke) and idle fairly well around 1K.  There was some high idle blips, knocking and cam chain sound so then I adjusted the valves, adjusted the cam chain tensioner (not sure if that has been doing anything though), adjusted the points gap, and set the ignition timing (it's a TEC).

The bike started once after I completed all that and it sounded much better.  When I went to start it again, it wouldn't start anymore.

Since then I've been redoing the points and ignition timing over and over again trying slight variations and every method I could find here.  Yesterday I took off the carbs again just in case but they looked very clean.

Sometimes I can get it to start for about 7-10 seconds but it begins to die immediately, even with full throttle.

I'm not sure what I could have done to cause this.  Could the cam chain cause this? 

The valves are spot on, and the points are at 0.013.  I've been using a multimeter to check for spark when the F is lined up with the timing mark.  I was planning on borrowing a strobe but now I can't get it running...

[dave500]

has fuel?how full is the tank and where is the fuel tap switched onto?if its on and only has a gallon youll need to switch it to reserve.