Topic: Dad's 1978 Honda CB550k

[joegeis]

Last updated: 8/29/23

Starting this post now (mostly as a placeholder, since I haven't made any progress yet!) I'm going to continue to update this top post as I go, but will add replies with details of each step and pictures, request for help, questions, etc. Please feel free to offer feedback or advice along the way. I'm a first timer!

PROJECT GOALS (listed here both as a reminder to myself and for anyone curious about what is guiding my decisions during the build)

• Make Dad's old bike something I enjoy riding regularly, and will want to keep and maintain.
• Improving rideability and reliability is a priority. Maximum performance is not.
• Loosely keep with the spirit of the original OEM design, but will make subtle changes due to necessity (part availability, cost) or for a personal preference. For example, I will not be redoing the chrome plating, and may paint some parts black, but I will not be installing clip ons.
• Leave much of the aging and patina (not repainting the tank, not vapor blasting the aluminum, but getting everything clean)

Short Term To-Do List:

• Wash!
• Replace oil, filters and battery
• Mystery Oil  each cylinder
• Drop & clean oil pan and oil filter. Test oil pressure
• Check for spark
• Try to start
• Rebuild and tune carbs
• Rebuild front end (wheels, tires, brake system, forks, wheel bearings, steering bearings)
• Rebuild rear end (wheels, tires, brake system, shocks, wheel bearings, swing arm bushings)
• Replace seat cover
• Test and fix controls, lights and electrical
• Replace fuseblock
• Install Hondaman's ignition

Overall Progress:

• Engine turns
• Rebuild carbs, replace all hoses
• Rebuild brakes
• Wheels, tires and bearings
• Lights / electrical
• Chrome / rust
• Mirrors, controls, grips
• Replace gear with broken tooth

Found this old photo (Dad and little brother on the bike, me putting his feet on the pegs. Circa 1999


Link to Photo Album


Current state:

[BenelliSEI]

Lots of work to do, but great it’s your Dad’s old bike! My first SOHC Honda was a ‘78 550K. A really fine machine. Good luck and ask questions!

[MauiK3]

Exhaust is a big issue for these isn’t it?

[joegeis]

Exhaust is a big issue for these isn’t it?

I've only seen a few for sale online and they are >$1500. If the current exhaust is too far gone, I'll swap for a 4 into 1, which I actually prefer the looks of. I have no idea how to deal with rust on chrome, but if I can minimize the rust and make these serviceable, I'll keep them.

[newday777]

Exhaust is a big issue for these isn’t it?

I've only seen a few for sale online and they are >$1500. If the current exhaust is too far gone, I'll swap for a 4 into 1, which I actually prefer the looks of. I have no idea how to deal with rust on chrome, but if I can minimize the rust and make these serviceable, I'll keep them.

Crumpled aluminum foil and Evaporust Gel.
Brush on the gel, cover with plastic wrap so the gel doesn't evaporate for an hour or two, the use the crumpled foil to rub over the surface to flatten out any pits, then rinse and dry.

https://www.evapo-rust.com/crc-evapo-rust-gel/

Delkevic makes a good 4into1 system for @$400.

[BenelliSEI]

The ‘77/78 550K pipes are extremely rare……  if those can be polished up and saved, they significantly increase the value of the bike (which in this case  of “Dad’s Old Bike”is probably not to important?).

[BenelliSEI]

Note that several parts on your model of 550 are interchangeable with  cb750 parts. For example, the front wheel/hub assembly is interchangeable, so spokes and rim are available today, at reasonable prices. The actual brake disc is unique, slightly smaller in diameter…. Master cylinder, head lamp, turn signals and tail light assembly too.

[joegeis]

Thanks for the tips! I was wondering how similar the 550 was to thr 750. I was wondering if I would be able to reuse the existing rims (probably painted black, since the existing finish it toast), after adding new spokes and replacing the bearings. I guess it will depend on the amount of rust? Or should I just get new wheels? Would it potentially be a safety issue?

[newday777]

Once you remove the old tires you will make a determination on the rims if rusted badly inside the rims or not.

[BenelliSEI]

As Stu says, you’ll know when you pull the tires. I’ve had some that just collapsed when levering off the tires, and then others that were spotless inside. My son had a set of rims powder coated black, and with shiny, new spokes, the wheels looked really lovely. Just depends on the look you prefer. I like to use new rims and spokes because nothing else gives you the appearance bang for the buck…….

[CycleRanger]

Good on you! That's a lot of "patina" but certainly a worthy project. Nice that it's all there and original. They're only that way once.

[joegeis]

Bike got a once over cleaning with the pressure washer and a little Marvel's Mystery Oil in each cylinder. Surprisingly only cylinder one's plug looked fowled. The other three looked like they would have still worked fine! Still picked up some new replacements of course though. I put the plugs back in and turn the kickstarter a few times. I'll change the oil and filter tomorrow. Still need to procure a battery though.

[newday777]

Bike got a once over cleaning with the pressure washer and a little Marvel's Mystery Oil in each cylinder. Surprisingly only cylinder one's plug looked fowled. The other three looked like they would have still worked fine! Still picked up some new replacements of course though. I put the plugs back in and turn the kickstarter a few times. I'll change the oil and filter tomorrow. Still need to procure a battery though.

Don't throw away the flat washer that sticks to the oil filter. You'll need it, it goes between the spring and the filter. It may be missing already? #8 in the fiche.

It'd be a good idea to drop the oil pan and clean the pump pickup screen. Look for chunks in the pan. If black chunks, post a picture. That could mean the cam chain tensioners are bad, needing replacement.

https://www.southsoundhonda.com/--xpartsstream#/Honda_Powersports/CB550KA_(78)_550_FOUR_K%2c_JPN%2c_VIN%23_CB550K-2100001_TO_CB550K-2122082/OIL_FILTER_%2b_OIL_PAN/0f12de96-474a-4fbe-a2ee-8ba2cda5f653/4514413a-2c99-4528-97b1-535c3c09e1c6/y

[BenelliSEI]

After you put in fresh oil (I usually use whatever 10W-30 is on sale, then drain it out after it gets good and hot the first few shop starts) and filter, pull the plugs and use bursts of the electric starter until the oil pressure light goes out. Good to make sure oil is in all the right places beforehand.

[BenelliSEI]

Before you try and start, pull off one of the outer float bowls (they are a pain) and see how much crud has accumulated there. If your petcock was “drooling” for years, there will be lots of debris left behind as the fuel evaporated. If that’s the case, DON’T TRY and START. You’ll only plug up the carbs and make your job harder. Pull them off and do the job right.

If the bowl is clean, go for it! Sometimes we get lucky.

[newday777]

Before you try and start, pull off one of the outer float bowls (they are a pain) and see how much crud has accumulated there. If your petcock was “drooling” for years, there will be lots of debris left behind as the fuel evaporated. If that’s the case, DON’T TRY and START. You’ll only plug up the carbs and make your job harder. Pull them off and do the job right.

If the bowl is clean, go for it! Sometimes we get lucky.

Totally agree 👍

[BenelliSEI]

You’re not going to have much luck painting those rims unless you deface the rim, and heavily scuff the rust and chrome finish off first. I’ve never seen a paint hold onto bad chrome or good chrome. If you go the dodgy route, it will look like it. You can’t hide shortcuts.

My son had a pair of rusty case guards and rims powder coated gloss black. I would have scrapped them, but he insisted. The shop blasted them hard and coated them well. I was impressed, they still very good……

[joegeis]

Before you try and start, pull off one of the outer float bowls (they are a pain) and see how much crud has accumulated there. If your petcock was “drooling” for years, there will be lots of debris left behind as the fuel evaporated. If that’s the case, DON’T TRY and START. You’ll only plug up the carbs and make your job harder. Pull them off and do the job right.

If the bowl is clean, go for it! Sometimes we get lucky.

Forgot to mention that I am still planning to pull the carbs, run them through the ultrasonic cleaner and rebuild with a kit I've got coming in the mail. The intent of attempting to start prior to is just to see if there is an electrical issue and if the engine gives any pops/bangs at all.

You’re not going to have much luck painting those rims unless you deface the rim, and heavily scuff the rust and chrome finish off first. I’ve never seen a paint hold onto bad chrome or good chrome. If you go the dodgy route, it will look like it. You can’t hide shortcuts.

My son had a pair of rusty case guards and rims powder coated gloss black. I would have scrapped them, but he insisted. The shop blasted them hard and coated them well. I was impressed, they still very good……

If these are toast, I would like to bob them a bit. If the cost isn't insane, I would love the look of coating them black. I've found a local shop I can reach out to.

[newday777]

Rather than try with your dirty carbs and plug them up further, just have the carbs off, squirt in some starter fluid in each intake and hit the starter button to get it to pop off.

[grcamna2]

Exhaust is a big issue for these isn’t it?

I've only seen a few for sale online and they are >$1500. If the current exhaust is too far gone, I'll swap for a 4 into 1, which I actually prefer the looks of. I have no idea how to deal with rust on chrome, but if I can minimize the rust and make these serviceable, I'll keep them.

Crumpled aluminum foil and Evaporust Gel.
Brush on the gel, cover with plastic wrap so the gel doesn't evaporate for an hour or two, the use the crumpled foil to rub over the surface to flatten out any pits, then rinse and dry.

https://www.evapo-rust.com/crc-evapo-rust-gel/

Delkevic makes a good 4into1 system for @$400.

Evaporust on the chrome  will restore it to the best it can be, w/o rechroming.

[joegeis]

Rather than try with your dirty carbs and plug them up further, just have the carbs off, squirt in some starter fluid in each intake and hit the starter button to get it to pop off.

ooooh, good idea!

[RAFster122s]

Remember most carb kits brass is not sized correct even if they have the correct size markings. Unless it is genuine Keihin brass don't use it, exception being JetsRUs brass is sized correctly.
Few can get aftermarket brass to work as it is a tuning nightmare because of fundamental size difference that don't work.

[BenelliSEI]

+1 to above! Soak all your brass in carb cleaner, the ultra sonic and blow. Unless some piece is broken, cracked or corroded, reuse the original. I usually buy a stack of bowl gaskets and reuse everything else…..

[Stev-o]

Soak all your brass in carb cleaner...

Confirm it is genuine Keihin first! 

[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!