Topic: Dad's 1978 Honda CB550k

[grcamna2]

I think that's great you found your title 

[RAFster122s]

Oil does Not get into the carb...it is a drop/drip/run from somewhere else. Don't chase what's not real...
Spray on foot powder can help you trace oil leaks after cleaning the engine you spray a thin coat of the foot powder that drys white. Subsequent ride or operation of the motor if you check early enough will show path of oil from the leak...

[Little_Phil]

3. Airbox boots

The boots to the airbox for the Pd carbs are longer than on all the earlier models. Make sure they are correct. They are not easily obtained. I was going to look into a way of using the shorter boots and pulling the airbox forward a bit, but haven't looked into it.

[joegeis]

Got the rear wheel back on, new chain installed, tension adjusted, rear brake rebuilt, etc. Rear tire feels like it will spin forever, it's so smooth!

I found these two little o rings and this very small washer in my parts box. They were not sorted into a bag, like all my other bolts, and I never ran across a spot where it seemed like they should go. I followed along my Haynes manual, the service manual and the microfiche. I'm completely at a loss. Any idea where these go?

[joegeis]

I took the front brake caliper apart. There was still a good amount of corrosion below the o-ring. I cleaned up really well and put everything back together and now the front brake works flawlessly. No dragging when not engaged, no squeaking, good bite and very firm lever.

I also went over the 4 exhaust pipes with a brass brush, steel wool and Evaporust. I have to say they look so much better than I ever thought they would. I'll post up some more pictures soon. There is one small hole rusted through the bottom of one of the mufflers. Does this matter?  I also find quite a lot of discoloration and carbon building on pipe 2 where is connects to the engine. Seems like one of the cylinders was running rich for a long time. I'll reinstall the exhaust later this week.

Finally, I tightened up the bolts on the oil pan. Several were able to take another quarter turn pretty easily. I'll see if that stops my oil leak. In the meantime, I have ordered a NOS gasket. The aftermarket 4into1 gasket didn't fit great, and if it still leaks, I'll be ready to replace it next time.

Next up is syncing the carbs, but I feel like I need some kind of solution on the airbox boot fitting on carb 3 and 4. I went back and looked at the pictures from when it came out of storage (attached), and you can tell that the boots were not fitting on carb 4 when i got it out of storage. I wonder if something was leaning on it and deformed the shape of the airbox or boot over time? I'm really at a loss on what to do. I never removed the boots from the airbox, and the airbox has not been bolted to the frame yet. It is still sitting loose behind the battery.

[grcamna2]

I took the front brake caliper apart. There was still a good amount of corrosion below the o-ring. I cleaned up really well and put everything back together and now the front brake works flawlessly. No dragging when not engaged, no squeaking, good bite and very firm lever.

I also went over the 4 exhaust pipes with a brass brush, steel wool and Evaporust. I have to say they look so much better than I ever thought they would. I'll post up some more pictures soon. There is one small hole rusted through the bottom of one of the mufflers. Does this matter?  I also find quite a lot of discoloration and carbon building on pipe 2 where is connects to the engine. Seems like one of the cylinders was running rich for a long time. I'll reinstall the exhaust later this week.

Finally, I tightened up the bolts on the oil pan. Several were able to take another quarter turn pretty easily. I'll see if that stops my oil leak. In the meantime, I have ordered a NOS gasket. The aftermarket 4into1 gasket didn't fit great, and if it still leaks, I'll be ready to replace it next time.

Next up is syncing the carbs, but I feel like I need some kind of solution on the airbox boot fitting on carb 3 and 4. I went back and looked at the pictures from when it came out of storage (attached), and you can tell that the boots were not fitting on carb 4 when i got it out of storage. I wonder if something was leaning on it and deformed the shape of the airbox or boot over time? I'm really at a loss on what to do. I never removed the boots from the airbox, and the airbox has not been bolted to the frame yet. It is still sitting loose behind the battery.

I recommend patching the hole on the one muffler so it doesn't get worse.I have used a small #0 torch tip to apply patches to holes in mufflers. I first cut out a fairly thin sheet metal patch a bit larger than the hole.
Prep the area around the hole first by using a small grinder to open it up until you have thick enough steel to braze to.

The airbox rubber needs to be the correct one for #4;the #1 and #4 should be a match so you can compare them to see. Have you ever tried using a Wintergreen oil mix to soak old rubber parts in before? There's a thread on here about it(uploaded a while back)and you can get the rubber boots to become more pliable so they will properly slip over the carbs. and hold with a clamp.

The picture of the #4 airbox rubber boot you uploaded is good;to me,it looks like that's the wrong boot in there.
The back side of the boot is removed from the airbox and it's still too short.

[newday777]

Unfortunately the 550 airbox rubber isn't available but you can rejuvenate it.

Soak the rubber in wintergreen oil and xylene mixture to soften them to be usable.
How to
http://forums.sohc4.net/index.php/topic,29707.0.html

Wintergreen – 100% Pure Essential Oil – GreenHealth 16 fl oz (473 ml) Glass Bottle with Child Resistant Cap https://a.co/d/2XBQfT7

https://www.homedepot.com/p/Klean-Strip-1-Gal-Xylene-Thins-Epoxies-and-Enamels-GXY24/100406366

[joegeis]

to clarify, its not that the boot is hard and I can't stretch it over the carb. It's that it appears to not be long enough.

I will measure and compare the boot lengths, however I don't think they have ever been removed from the airbox.

[joegeis]

Got the exhaust back on today. The copper crush gaskets were not a great fit, and I felt like I had to really torque down the nuts (rounded one even) to get a good seal. The old ones that came out seemed to be at least partially fiber, and were not magnetic. Strange.  Here are some pictures as the bike is finally starting to come back together. I also cleaned up the oil on the pan and put cardboard under the bike to find out if its still leaking. Later this week I'll be attempting a carb sync, at least as much as possible given the airbox situation on carb 3 and 4. I'm really at a loss for what to do. I may just run it as is or maybe even consider pods as a last resort. This seems like such a silly problem.

Also, in the last picture, you can see the side stand hits the exhaust. I don't recall if this happened before. Is this normal?

[RAFster122s]

Fitting the exhaust can be a challenge sometimes. Best to get things lined up at the back and work back and forth from front to rear on tightening things down checking to ensure the front isn't twisting out of place.
As far as the gaskets go there are the tubular copper gaskets and the other style has heat resistant cardstock between metal rings on outside and inside perimeter. The paper distorts or confirms to the sealing surfaces when you tighten things down.
You will need to replace the rounded nut the next time you have to pull the exhaust or tweak it. Sounds like things were not aligned correctly for you to round the nut getting things to pull in correctly.

The exhaust isn't aligned correctly if your side stand is interfering with the exhaust. It is a big 3D puzzle you are putting back together and it frustrates most of us to some degree refitting an exhaust.
Sometimes you have to walk away from it and restart on another day. Never hurts to have spare copper crush washers for the header pipes on hand. They are easy to mess up and cranking down on them trying to force them to seal when things aren't aligned just right usually is a short term "fix" that a few heat cycles cause things to come undone and leak.

[Little_Phil]

to clarify, its not that the boot is hard and I can't stretch it over the carb. It's that it appears to not be long enough.

I will measure and compare the boot lengths, however I don't think they have ever been removed from the airbox.

I would remove the clamp and see if the boot will fit better by twisting it round. There is an alignment bobble of rubber on the grommet section of the boot that fits to the airbox. It should face inwards.  Difficult to describe length but the 40mm O/D section of the boot should be at least 25mm long if it is the correct boot.

[grcamna2]

Pull that airbox/collector back off and swap the 4) different rubber inlet hoses around from one hole to the other until you can sight across all of them from #1 #2 #3 & #4 So that they're all even with each other,straight across;use a straight-edge if necessary.
I think they have been removed before.

[joegeis]

alrighty, I'll pull the airbox and air manifold back out. I'll ensure everything is still flexible and that the ends of the boots are all nicely aligned. I'll also ensure the intake of the carbs are perfectly aligned as well.  I'll take plenty of pictures and we can decide what's next

[joegeis]

Okay, as much as it hurt to take the carb back out after fighting so hard to get it in, I did it! Airbox and plenum are out. Pictures below. To me, things seem to stack up evenly. If anything, air boot 3 is shorter than the rest, with 1 and 4 being about even. I did replace the intake manifold rubbers with aftermarket. Is it possible that I was able to push the carb too far forward? I didn't look before I removed the carb. I did compare the new and old, and they are the same length. Do you see anything in these pictures that could be leading to the issue? Boots 1 & 4 measured 30mm and 2 & 3 measured 18mm. I have more pictures not below in the album here. Scroll to the bottom.



Also that oil leak is worse than ever! Seems to be coming from the back of the pan. I don't see oil from anywhere higher on the bike, and I also haven't disturbed any other oil seals except the pan gasket since changing the oil.

[joegeis]

Ok, after inspecting all the pieces off the bike, everything looked good to me.

1. I reinstalled the carb, ensuring the boots were seated evenly on the engine intake.
2. I connected the airbox plenum boots to the carb intake. Everything fits. However I notice the carb box is so far forward there is no way I'm getting the clutch cable reattached.
3. I connect the air plenum to the air cleaner box. So far so good.
4. I mount the airbox to the frame. Here we have a problem. The plenum is much too far forward and down. I pull so hard to line up the airbox mounting holes with the frame, that the plenum boots 3 & 4 pull free from the carb intake. Now it looks like it did before. HOWEVER, the airbox plenum is now in what appears to be the right position (because it mates to the airbox and frame and it makes the perfect amount of room for the clutch cable to pass.

I think this means that my carbs are in the wrong place. Too low and too far forward. How the hell could that be possible? I replaced the intake boots with these , which I measured and match the OEM perfectly. I'll post pictures later, but they are up on the shared album https://photos.app.goo.gl/yqMD7iLYyYHFVBuo7

[grcamna2]

Ok, after inspecting all the pieces off the bike, everything looked good to me.

1. I reinstalled the carb, ensuring the boots were seated evenly on the engine intake.
2. I connected the airbox plenum boots to the carb intake. Everything fits. However I notice the carb box is so far forward there is no way I'm getting the clutch cable reattached.
3. I connect the air plenum to the air cleaner box. So far so good.
4. I mount the airbox to the frame. Here we have a problem. The plenum is much too far forward and down. I pull so hard to line up the airbox mounting holes with the frame, that the plenum boots 3 & 4 pull free from the carb intake. Now it looks like it did before. HOWEVER, the airbox plenum is now in what appears to be the right position (because it mates to the airbox and frame and it makes the perfect amount of room for the clutch cable to pass.

I think this means that my carbs are in the wrong place. Too low and too far forward. How the hell could that be possible? I replaced the intake boots with these , which I measured and match the OEM perfectly. I'll post pictures later, but they are up on the shared album https://photos.app.goo.gl/yqMD7iLYyYHFVBuo7

Would the 4) new intake boots be pushed onto the engine too far;would loosening them and pulling them all back a specified amount and reclamping all 4 of them evenly,then installing the carbs again help ?

[joegeis]

Ok, after inspecting all the pieces off the bike, everything looked good to me.

1. I reinstalled the carb, ensuring the boots were seated evenly on the engine intake.
2. I connected the airbox plenum boots to the carb intake. Everything fits. However I notice the carb box is so far forward there is no way I'm getting the clutch cable reattached.
3. I connect the air plenum to the air cleaner box. So far so good.
4. I mount the airbox to the frame. Here we have a problem. The plenum is much too far forward and down. I pull so hard to line up the airbox mounting holes with the frame, that the plenum boots 3 & 4 pull free from the carb intake. Now it looks like it did before. HOWEVER, the airbox plenum is now in what appears to be the right position (because it mates to the airbox and frame and it makes the perfect amount of room for the clutch cable to pass.

I think this means that my carbs are in the wrong place. Too low and too far forward. How the hell could that be possible? I replaced the intake boots with these , which I measured and match the OEM perfectly. I'll post pictures later, but they are up on the shared album https://photos.app.goo.gl/yqMD7iLYyYHFVBuo7

Would the 4) new intake boots be pushed onto the engine too far;would loosening them and pulling them all back a specified amount and reclamping all 4 of them evenly,then installing the carbs again help ?

There is a ridge on the inside of the boot that sits in a groove on the intake, making it nest together. My worry is that backing it off that groove would make the connection weaker. I'm also not sure there is enough there to close the gap. I'll explore it this evening though. Thanks for the suggestion.

[joegeis]

I just tried fiddling around with it again. Between pulling the airbox boots forward and pushing the carb back, it just seems like there isn't enough "rope" to make the ends meet on carbs 3 & 4. I just can't understand it. I've scoured the internet and this forums and it seems like this is a unique problem (which probably means its something simple and stupid). There seem to be no aftermarket options for CB550 K4 airbox boots. Apparently, the K4 is different from all other years (as are my carbs). I am so frustrated!

Options I see:
1. Wrap it in duct tape.
2. Switch to pods (and go through a new headache of rejetting the carbs)
3. Say f*ck it and leave as-is.
4. ?

I might just have to go with option three for now. I need to fix my oil leak, replace my hoses, sync the carbs and get this thing on the road.

[grcamna2]

Could one side(#3 & #4)of the airbox plenum be warped back ?

The carbs. you have will not like pods..
I think wrapping some HD 3M rubber tape between the #4 carb. throat and rubber tube is a temporary option.
I've never seen this problem before.

[RAFster122s]

Where did the airbox boots and intake rubber boots come from??

[joegeis]

the airbox boots were on the bike when it went in to storage ~25 years ago. You can see in the original picture a few posts up that carb 4 wasn't connected to the airbox when I pulled it out of storage.  Also a few posts up in held the plenum up to my shiny cabinet and it appears that each boot lines up for the most part (2&3 look a little short). I thought about heating and bending the plenum forward to compensate, but that will interfere with the clutch cable.

Going to pods is a last resort. I REALLY don't want to do that. I think I would just replace my carbs and all with the Murray's kit if I go that route, but its not the direction I want to take this build.

Is this the kind of tape you are referring to?

[grcamna2]

the airbox boots were on the bike when it went in to storage ~25 years ago. You can see in the original picture a few posts up that carb 4 wasn't connected to the airbox when I pulled it out of storage.  Also a few posts up in held the plenum up to my shiny cabinet and it appears that each boot lines up for the most part (2&3 look a little short). I thought about heating and bending the plenum forward to compensate, but that will interfere with the clutch cable.

Going to pods is a last resort. I REALLY don't want to do that. I think I would just replace my carbs and all with the Murray's kit if I go that route, but its not the direction I want to take this build.

Is this the kind of tape you are referring to?

That tape is the quality I was hoping,even though it's only 3/4" wide.
I hope you're able to get wider tape.

[joegeis]

the airbox boots were on the bike when it went in to storage ~25 years ago. You can see in the original picture a few posts up that carb 4 wasn't connected to the airbox when I pulled it out of storage.  Also a few posts up in held the plenum up to my shiny cabinet and it appears that each boot lines up for the most part (2&3 look a little short). I thought about heating and bending the plenum forward to compensate, but that will interfere with the clutch cable.

Going to pods is a last resort. I REALLY don't want to do that. I think I would just replace my carbs and all with the Murray's kit if I go that route, but its not the direction I want to take this build.

Is this the kind of tape you are referring to?

there are a few widths available. I'll grab one that an inch or so
That tape is the quality I was hoping,even though it's only 3/4" wide.
I hope you're able to get wider tape.

[grcamna2]

I was also considering if you were to get a proper o.d. short length(the stuff is thin wall)of steel electrical conduit pipe(or copper pipe?)to put inside the gap between the rubber hose and carb.;push it into the rubber air tube section,then butt it up to the carb body.
I think it's possible to even clamp down onto it from the side of the rubber flange after it's all taped.

[Little_Phil]

The longer boots for the Pd carbs were available from Paul Gabor on mybluebike2004@yahoo.com,  I think he made them. They were not as robust as the originals, but can be used with care on assembly.