Topic: Dad's 1978 Honda CB550k

[BenelliSEI]

Soak all your brass in carb cleaner...

Confirm it is genuine Keihin first!

Excellent point! If someone has used poor quality stuff you can end up frustrated for months!

[RAFster122s]

Genuine Keihin will have the stylized K stamped in it...just like written on side of carbs, that logo letter. You may need magnifying glasses for numbers and the like... Or use zoom on your phone when jets are lighted well...

[joegeis]

Okay, today was the first day actually starting to work on the bike. I accomplished a few things:

• Removed and drained gas tank. It was FULL and the gas was still in great shape. Honestly, it was probably good enough to run!
• Drained oil, removed oil pan and strainer. Cleaned all parts
• Removed what was left of the old airbox and battery
• Removed carbs

Findings:

• gas tank has no rust and petcock still works with no leaks!
• airbox is in rough shape, but I can't find any online that are in any better shape, and I haven't come across any reproduction parts yet. I'll probably try to gently put it back together and hope for the best.
• Haven't checked the bowls yet, but overall carbs seem in decent condition
• Oil was full and pretty clean. Dad must have changed the oil right before storing it
• Found a small bit of aluminum in the oil pan. I haven't been able to identify where it came from yet. There was also some grit in the oil pan. Felt almost like sand grains, but too small to show up on camera. You can see the sludge in the oil filer and pan in the pictures though.
• Oil strainer seemed very clean and in good condition. Only a few small specs stuck in the screen.

I've ordered a handful of gaskets and seal kits. I'm going to replace the oil pan gasket and the oil filter housing and tube gaskets as well. I'm running all the parts through the ultrasonic after a good hand scrubbing. I've noticed quite a bit of surface rust on the frame, and on the engine (especially this small plate, as you can see in the pictures). I'll need to decide what (if anything) I'm going to do about it. I assume a wire wheel and some black paint would remedy the surface rust on the frame, and using an evaporust soaked rag on the engine?

My carb rebuild kit came in the mail today too, so tomorrow I'll tear the carbs down and give them a thorough cleaning. I am going to replace all gaskets, but will reuse the bowls and all the brass as long as nothing is damaged. Hopefully I'll get so far as to reassemble and bench sync too. I'm not sure if I have the right hoses for replacing the fuel and drain lines. Here is what I bought. https://4into1.com/grey-fuel-vent-line-3-5mm-1-meter-3-feet/ & https://4into1.com/grey-fuel-vent-line-3-5mm-1-meter-3-feet/

Also working on upgrading my workshop. I built a few cabinets, and did some organization. Still waiting on my new toolbox to arrive though...

Should I use some type of oil or sealant on gaskets as I install new ones? 3in1 oil or some permatex product?


More photos in album, as always.

[RAFster122s]

The rusty cover over the starter motor is chromed steel, you may wish to avoid use of dny wire brushes. Soaking in phosphoric acid or Evaporust would be safer.

[grcamna2]

I can't view the pictures..

[newday777]

"Findings:
gas tank has no rust and petcock still works with no leaks!
airbox is in rough shape, but I can't find any online that are in any better shape, and I haven't come across any reproduction parts yet. I'll probably try to gently put it back together and hope for the best.
Haven't checked the bowls yet, but overall carbs seem in decent condition
Oil was full and pretty clean. Dad must have changed the oil right before storing it
Found a small bit of aluminum in the oil pan. I haven't been able to identify where it came from yet. There was also some grit in the oil pan. Felt almost like sand grains, but too small to show up on camera. You can see the sludge in the oil filer and pan in the pictures though.
Oil strainer seemed very clean and in good condition. Only a few small specs stuck in the screen."

Great findings actually. Yes dad must have changed the oil.
The chunk of aluminum might be a piece of the casting that I've read gets commonly busted off, I don't remember the reason as I haven't worked on the 550 motors. Someone that knows them should be along.
The airbox looks OK from what I see. The powder in the screen looks like disintegrated foam filter???
What do you mean by it looks rough?
You can soak the rubbers in a wintergreen oil/acetone mix (or brake fluid)to soften them to reuse(might not find new NOS rubbers)

The 3.5mm hose is for the carb drains and vents. You'll need 5.5mm for the gas supply lines. Measure the old hose lengths to see if you have enough.

Use a light coating of engine oil on the gaskets.

[joegeis]

I can't view the pictures..

Sorry about that. I changed the way I posted them. Did that fix it?

[joegeis]

What do you mean by it looks rough?
You can soak the rubbers in a wintergreen oil/acetone mix (or brake fluid)to soften them to reuse(might not find new NOS rubbers)

The 3.5mm hose is for the carb drains and vents. You'll need 5.5mm for the gas supply lines. Measure the old hose lengths to see if you have enough.

I fixed the photos in my last post. The boots (not sure what they are actually called) that connect to the carbs are pulling away from the airbox housing, and one of them is a little chewed up. I'll probably just remove and recondition the whole thing and reuse it. Looks like I am going to need more than 3 feet of 3.5mm hose. I assume I can probably pick up a roll of that at an auto parts store. Shouldn't need anything fancy for drain lines I imagine.

[joegeis]

forgot to ask - as I start putting everything back together, should i put anything on the the screw threads? anti-seize or loctite? nothing?

[grcamna2]

I can't view the pictures..

Sorry about that. I changed the way I posted them. Did that fix it?

Yes,I can see the pictures now,thanks. 

You might use a light coating of silver Never Seize on a few threads during reassembly.

[scottly]

Are you sure that small chunk is aluminum and not steel? Check it with a magnet. It looks a lot like a "dog" from a gear in the transmission.

[MRieck]

Are you sure that small chunk is aluminum and not steel? Check it with a magnet. It looks a lot like a "dog" from a gear in the transmission.

It sure does.

[joegeis]

Are you sure that small chunk is aluminum and not steel? Check it with a magnet. It looks a lot like a "dog" from a gear in the transmission.

You are right, it is magnetic! It was so light, I thought it was aluminum! So what does this mean? Should I expect some issues in the transmission?

[joegeis]

So I started taking apart the carb, and I've gotten a little stuck, and can't figure out how to proceed. Both the Clymer manual and Youtube are not seeing me through!

First, my carb is different from the one being shown in this video. I do not have these little wing clips as shown at 7:59. Maybe I don't need them with this model carb? He doesn't say what year CB550 he is working on, so maybe they changed them at some point. Or maybe my carbs are aftermarket? I would be really shocked if that was the case though.

Second, I can't seem to figure out how to separate the individual carbs. It seems like the rod connecting the butterfly valves (not sure if thats what they are called - the valves controlled by the throttle) is just one piece, so I don't see how to pull them apart!

Overall the carbs are super clean. Nothing is seized or varnished. The bowl gaskets are completely petrified and rock hard. I have the whole carb assembly in the ultrasonic right now. I'm hoping that loosens something up and softens the gaskets enough to remove them.

[grcamna2]

So I started taking apart the carb, and I've gotten a little stuck, and can't figure out how to proceed. Both the Clymer manual and Youtube are not seeing me through!

First, my carb is different from the one being shown in this video. I do not have these little wing clips as shown at 7:59. Maybe I don't need them with this model carb? He doesn't say what year CB550 he is working on, so maybe they changed them at some point. Or maybe my carbs are aftermarket? I would be really shocked if that was the case though.

Second, I can't seem to figure out how to separate the individual carbs. It seems like the rod connecting the butterfly valves (not sure if thats what they are called - the valves controlled by the throttle) is just one piece, so I don't see how to pull them apart!

Overall the carbs are super clean. Nothing is seized or varnished. The bowl gaskets are completely petrified and rock hard. I have the whole carb assembly in the ultrasonic right now. I'm hoping that loosens something up and softens the gaskets enough to remove them.

The 78' CB550 you have has 'PD' model Keihin carbs stock;they are different than the older ones.

[CycleRanger]

You can download the Honda 550 shop manual and parts list from here:
https://www.honda4fun.com/materiale/documentazione-tecnica

Just scroll down a bit.

You'll find the manuals much better than the Clymer one.
Those carbs look amazing considering the age of the bike and how long it sat.
And yeah, you're going to have to find the source of that steel piece you found.

[newday777]

Just doing some web searching to find the carb numbers and differences, there are different carb numbers for the 77 and the 78 carbs that you need to identify which carbs you have. Look on the flat surface above the bowls for the carb body ID stamped into the flat surface. (I'm not sure why there is different ID numbers referenced in the charts pictures I'm attaching and what Brain Barnes says the 78 has PD46A?? Again I don't know the 550...so do some more research and hopefully someone will correct this information as to identify your carbs) Hondaman was going to publish a book on the CB500/550 like he did on the CB750, but hasn't finished yet to my limited knowledge on the 550, so maybe he'll get a chance to chime in here.

If your bike is an actual 78 as you say it should have the PD46C carbs (77 had X46A with smaller slow jet 38 than the 78 PD46C with 42 slow jet) from chart pictures below I got from the 550 information page on the forum page

http://www.sohc4.com/cb550/cb550/

Here is a carb rebuild writeup by Brian Barnes on the 78 PD46A carbs

https://s3.amazonaws.com/sohc4-tech/CB550/PD46A_rebuild.pdf

[joegeis]

Went back out last night to check. Carb is stamped 46C A PL. I'll take a closer look at the resources you posted after work tonight.  Thank you!

[flatlander]

Are you sure that small chunk is aluminum and not steel? Check it with a magnet. It looks a lot like a "dog" from a gear in the transmission.

You are right, it is magnetic! It was so light, I thought it was aluminum! So what does this mean? Should I expect some issues in the transmission?

i agree, that's what it looks like.
unless you find a different source of this piece, it will mean that you'll have to split the cases and replace the gear that it came from.

re. the carbs:
is there a reason why you want to separate them and take them totally apart? unless you have a specific problem, i wouldn't do that, it's not usually necessary. cleaning the jets, the bowls and replacing the rubber gaskets should be sufficient.

re. airbox parts:
most of it looks usable, i don't see why you would need to replace the whole lot. if the carb boots and those rubber pieces between airbox and carb aren't ok you can get new ones and replace them. a way to search for sources is to stick the honda part number in your internet search engine. apart from these, get a new paper airfilter and for the oil separator that lives at the bottom of the airbox, you can cut a new filter out of filter foam that you can buy.

starter motor cover:
i'd just get a new or second hand one in good condition.

do check your rims and spokes, they do seem to have a lot of rust. i presume you'll at least replace the tires anyway?

[joegeis]

Are you sure that small chunk is aluminum and not steel? Check it with a magnet. It looks a lot like a "dog" from a gear in the transmission.

You are right, it is magnetic! It was so light, I thought it was aluminum! So what does this mean? Should I expect some issues in the transmission?

i agree, that's what it looks like.
unless you find a different source of this piece, it will mean that you'll have to split the cases and replace the gear that it came from.

re. the carbs:
is there a reason why you want to separate them and take them totally apart? unless you have a specific problem, i wouldn't do that, it's not usually necessary. cleaning the jets, the bowls and replacing the rubber gaskets should be sufficient.

re. airbox parts:
most of it looks usable, i don't see why you would need to replace the whole lot. if the carb boots and those rubber pieces between airbox and carb aren't ok you can get new ones and replace them. a way to search for sources is to stick the honda part number in your internet search engine. apart from these, get a new paper airfilter and for the oil separator that lives at the bottom of the airbox, you can cut a new filter out of filter foam that you can buy.

starter motor cover:
i'd just get a new or second hand one in good condition.

do check your rims and spokes, they do seem to have a lot of rust. i presume you'll at least replace the tires anyway?

GEARBOX - Okay, I'll mentally file that away for now! I'm sure I'll be digging into the gearbox at some point in the future!

AIRBOX - I bought a foam replacement for the paper air filter. I run a foam filter on my new bike and like being able to clean and reuse it, so I figured I would do the same for this bike. What was left on the bike was totally disintegrated, so I didn't realize that the thing in the bottom was the oil separator and not part of the filter. Thanks for the heads up on that!

CARBS - No real reason I suppose. I expected them to be in bad shape and require a full tear down. I guess I just wanted to do it for the experience?

STARTER MOTOR - I'll hit it with evaporust and see how it looks. I'll keep my eye peeled for one in better condition.

WHEELS - I'm thinking its going to be easiest to just buy new wheels. The rust is so bad that I don't think its going to be worth the effort an cost to sandblast and repaint them. I'm going to replace the tires as well.

Thanks!

[flatlander]

AIRBOX - I bought a foam replacement for the paper air filter. I run a foam filter on my new bike and like being able to clean and reuse it, so I figured I would do the same for this bike. What was left on the bike was totally disintegrated, so I didn't realize that the thing in the bottom was the oil separator and not part of the filter. Thanks for the heads up on that!

yeah that thing at the bottom is where the vent hose from the crank case enters. those fumes can contain some oil that a filter element down there is meant to catch.
i tried a uni foam filter in the airbox once. it may not matter to you but i found it to be more restrictive than the OEM paper filter. i do have a modified engine and use it at higher rpms. my experience is that in a standard engine, if you don't only use it quite sluggishly, the OEM filter works best.

CARBS - No real reason I suppose. I expected them to be in bad shape and require a full tear down. I guess I just wanted to do it for the experience?

i wouldn't do it unless you actually find a problem. getting the linkage back together and syncing it all up properly will be a headache.

WHEELS - I'm thinking its going to be easiest to just buy new wheels. The rust is so bad that I don't think its going to be worth the effort an cost to sandblast and repaint them. I'm going to replace the tires as well.

i had original wheels on my 550 that were in good shape - much better preserved then yours. but when i switched to excel rims with stainless spokes it was a world of a difference in handling and stability. it's a very useful upgrade, if you want to go down that route. of course, it won't be or look original any more which is a disadvantage to some.

[Little_Phil]

CARBS - No real reason I suppose. I expected them to be in bad shape and require a full tear down. I guess I just wanted to do it for the experience?

i wouldn't do it unless you actually find a problem. getting the linkage back together and syncing it all up properly will be a headache

I would head Flatlander's warning. Getting the double spring choke mechanism back together between 2 and 3 is a mare. Only reason to split them is if the connecting pipes between carbs are leaking.

[joegeis]

slowly been working on the carbs in the evening this week. Everything is just about back together now. I had to replace the float on #4 but otherwise only replaced gaskets - everything else seemed in good shape. Also, my floats were all at 12.5mm. I've read that both 12.5 and 14.5 are the "correct" height for this bike. Since it seemed like it was previously set at 12.5, thats how I left them.

Also, I spoke to my mom about the bike. In the late 90's they got the bike out of storage and actually brought it to a Honda dealer to get it running because Mom wanted to start riding again (she crashed her CB350 when she was a teen and never rode again). She got on it once and got nervous and they parked it. I never knew! It also explains why the bike was in such great shape when it was stored.

I'm still waiting on my gasket kit to put the oil pan and filter back on, so the only other thing I can do in the meantime is start testing the electrical system, which is next. Assuming (and its a big assumption), that the work I've done so far is correct, the electrical system still works and there are no gremlins hiding in the engine, it should be running soon! I think I'll start working my way from front to rear for the rest. I want to start getting parts on order so I'm not waiting. I decided to play it safe and simply replace the wheels rather than try and restore them. That said, I'm struggling to find the right rims. Is there a consensus on best replacement wheels? I'm really looking more for good value than high performance. Definitely looking for some guidance on this one. I would like to go with black aluminum rims and stainless spokes. So far I found these, but they only come in chrome

https://www.dimecitycycles.com/rim-rr-18quotx185-chrome-kh400-s2-s3-cb550-500-450.html?fits-motorcycle=Honda/CB550/CB550%20550%20Four/1978
https://www.dimecitycycles.com/front-stainless-steel-spoke-set-cb750-cb550-cb450.html

I'll also be needing a brake rebuild kit, new cables and a master cylinder rebuild kit. The master cylinder may even need to be replaced. It's completely corroded and the lever is frozen.

I'll be polishing the forks and changing the oil. How do the springs hold up? Are those worth replacing? I'm only 175lbs, so I don't really need to account for extra weight, but if they are likely going to be pogo sticks, I would rather replace while I have everything taken apart.

Besides that, I'll replace the steering head bearing.

Is there anything else I should add to my checklist for the front end?

[newday777]

Cognitomoto has Sun aluminum rims.

https://cognitomoto.com/products/sun-aluminum-rims

[newday777]

Rims and spokes available at Buchanan

https://www.buchananspokes.com/products/spoke_kits_honda_cb.asp