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Adventure Honda CB550 On Machines On Motorcycles On Motorcycles

Honda CB 550 Motorcycle Build

In 2019 I purchased a Honda CB550 motorcycle. The year on the front plate is 1974. Which happens to be the first year the CB550 was introduced.

Honda had raced the 500cc in the World Grand Prix. But in 1969 the FIM introduced new rules (including weight minimums, a maximum number of cylinders and a maximum of six speeds). Honda walked out. And didn’t declare their return until 1977.

Soichiro Honda, the founder of Honda, loved racing and the progress in technology that resulted. The 500cc was the creme de la creme of GP racing at the time. But, having departed the GP, Honda was left without a production 500cc engine to advance. Surprise surprise, the following year Honda released the CB500 in 1971.

Honda spent a lot of focus on the 500 engine, releasing the CB550 in 1974, which replaced the outgoing CB500 with a larger displacement, faster acceleration, and the ability to mount dual front disc brakes. This may have been surprising to the motorcycling world. But Yoshimura, who lead Honda’s 500cc engineering return to the GP, joined Honda in 1972. Remarked, he was tasked, “to create something that would represent the very best in technology. We were determined to create an engine to surprise the whole world.”

Then in 1979 Honda debuted in the Grand Prix with a new 500cc engine. While 2 stroke engines were by now considered an advantage on the racing circuit, “Nonetheless, Honda wanted an engine that displayed a level of originality that fitted in with the business principles laid out by its founding father. The result was an engine unlike anything ever seen before in the racing world—a high-revving four-stroke, four-cylinder unit, with unique oval-shaped pistons that gave the visual impression of a V8.” [Honda]

The CB 500 and CB 550 are part of this story. The build:

I had purchased a 1982 Honda CB750 in 2013. But after a house reno and an undiagnosed electrical problem, the bike remained a non-runner 5 years later. So when I saw a running CB550 project bike for sale in the classifieds, I jumped on the opportunity.

Viewing the bike for the second time. It was frozen solid on my first viewing, so was inside to thaw

But it wasn’t without its issues. As I would soon discover.

Job 1: Clean the bike

It was covered with wax, dirt and everything in between. It was used in a film and the set crew had gone to town with it. Turned out to be a much bigger task than expected. And really the bike needed a total respray.

Job 2: It was running rich. So my first mechanical job was to sort that out.

I wrote a full post about tuning the carburetors over here.

Turns out that it was actually running lean with one cylinder running very rich. This was not the last I would see of these carbs.

Carburetors disassembled to clean and rebuild

Job 3: Deal with bondo cracks in the gas tank

I sanded the bondo to remove the cracked filler. Originally I was going to simply fill the holes, but the more I sanded the more damage was revealed.

Initial sanding of the filler

I took it to Bill a man gifted at paintless dent repair. He did an amazing job with the tank. So good that I was tempted to keep the tank metal and clear coat it. I may still do this in the future.

Return from Bill’s with a dent free tank

Job 4: Rebuild the forks

The front forks were rusted. So I decided to remove them to restore them and give them a full rebuild at the same time.

Unrestored front forks

After removing the rust and polishing them, I dissembled and cleaned the inner workings. The oil that came out of these forks was the most foul smelling stuff of legend.

Disassembled front forks off the CB550

I ordered new gaitors and reassembled.

Job 5: Respray the frame

The frame had been painted silver. Then over sprayed flat black, then sanded back to the silver. It needed respraying.

We were getting ready to move homes, so rather than doing an engine out powder coating, I purchased good quality caliper paint from Lordco and sprayed the frame in place. (I plan on doing a proper frame restoration down the road).

First step is to clean the frame from all oil, wax and grease. Use a good wax and grease remover. Step 2 is to sand the entire area you are painting. Remove any loose chips (this bike had many) and sand smooth. Step 3 is to wipe clean of dust. Step 4. Prime. Step 5. Apply your coat.

Frame looking fresh after the respray

My wife and I then went to the ski hill for a few days.

Job 6: Sell my old 1982 Honda CB750 bike.

There was a lineup of people wanting to buy it. Ended up meeting a really cool guy who rebuilt bikes. And he picked it up in his mini van. Hilarious.

Making bike friends
There’s a first for everything. CB750 loaded in a minivan.

Job 7: Rebuild the brakes

I had to replace the brake fluid cylinder, lever and all brake lines. Also replaced the brake pads. Topped up the brake fluid. I did learn a lesson. I mistakenly pulled the brake lever while testing it with the disc out. That was a fun job opening the brake again. With the wheel in, the brake adjusted we were good to go.

I don’t have many photos of this job. I did purchase the mounting kit and a second caliper and disc to convert the front wheel to a dual disc at the same time. Which I will post about when I do the conversion in the near future.

Measuring all gaps prior to rebuilding and cleaning the front brakes.

My bro and I then headed to Facebook’s F8 developer conference in San Jose California.

Job 8: Paint the tank

While the tank was painted maroon for the movie, the insurance papers for the bike shows the original color as blue. So rather than inviting an inspection when reinsuring it. I opted to paint the tank blue again.

Painting is fairly straight forward. Sand everything smooth. Fill any holes/scratches. Clean it with a wax and grease remove. Wipe clean with a lint free rag. Prime. Sand. Clean. Prime again. Sand again with a 400 grit wet sand paper. Clean. I used spray paint to spray the tank with the top coat. Be sure to spray it in a shady and dust free area. Flash drying in heat and direct sun causes cracks. Painting after the rain is a good time as it clears pollen. Do 3 coats of top coat. Light at first. The final coat makes everything smooth. Sand with 800 grit wet sand paper if desired. Clear coat.

Painting the tank outside.

Other jobs

Oil change, new spark plugs, new battery (twice), timing, tightened the cam chain, set valve clearances, synced the carbs, wrapped the exhaust, and replaced/installed missing or broken components (such as the tachometer, seat lock, ignition, you name it).

I wrote a complete guide on how to tune your CB550 for pods here.

(Oh and I moved in the middle of this build)

Syncing carbs on the 4-stroke CB550

The bike is not showroom perfect, it has a ton of character, and rather than making everything like new, I’ve kept the original side emblems as they were, and the engine fins, which are chipped, are now clean, but not polished, as it tells the story. And honestly, I love it.

Build complete

I road the bike to my dad’s place to show him. He got real quiet. I was wondering why… Then he shared how he road an early 70 Honda CB250 bike very similar to this when my mom was pregnant. Coincidentally it had a blue and white tank, almost identical to the one on this bike. I knew none of this.

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Adventure Essays Honda CB550 On Machines On Motorcycles

Unearthing the history of a 1974 Honda CB550

Hints of the story behind a Honda CB550 that is what it shouldn’t be.

When I went to look at a cb550 after it caught my attention browsing through the classifieds, I saw a rugged, characterful and misused motor with some semblance of charm. It was icy outside, so after taking the bike indoors to let it thaw, I returned the following day to hear it run. With the tap of a button the engine roared to life. Within an instant a connection formed, almost like meeting an old friend after many years.

The year was 2019 and with 45 years under its belt, having been built in Japan and driven across North America, I knew it would have stories. If only it could speak.

Laden with dirt, grease and wax the bike looked worse for wear. Tom, the prior owner of the bike, mentioned to me that he had rented to it to a movie production and their costume and set team had had their way. I couldn’t wait to get a rag and some soap to it.

As the bike stood, February 13 2019

But that’s when hints of a story began to emerge.

I noticed that the badly painted gas tank (again thanks in part to the apparent movie set team) had bondo cracks. So I called Bill, a talented dent repair specialist, if he would be able to take a look at it. “Sure,” he said, being a fellow bike guy. But mentioned that gas tanks were anything but easy when it came to popping dents.

Well that night I began the arduous work of sanding the bondo from the tank and prepping it for Bill. Yet as I peeled away the layers of old repairs and paint, more and more dents appeared. Clearly this bike had seen adventure.

Bill’s face lit with amazement when I showed him the tank. But faithful to his word he did his best. I was blown away by the difference. The once brutally damaged tank was enhanced to a patina that matched its age. I could almost hear my new old friend smile.

Tom had mentioned the bike was running rich. So I carefully tore open the carburetors. Meticulously organizing as I went. Someone, long ago, had rebuilt these carburetors before me. And had used some sort of seal gasket glue on everything, filling critical pathways and even covering the holes of the drain screws – which had been glued closed. It was obvious that others had since tried loosening them. Fortunately I had this incredible cleaner on hand. It’s probably toxic and deadly but eats through anything, so I love it.

The tear down begins

I found the source of the fuel mixture issue. The number 4 gasket was missing the needle. That would do it. Clearly someone else had discovered this too. The piston in the same carburetor was dented and bent from what appears to have been the work of a nonsamurai master. Fortunately, a file and carb cleaner made short work of the worst of it and the piston was removed. After addressing any issues, fixing all bent components and bolting it back together the carburetor looked and functioned as good as new… almost. The number 4 exhaust was cold after firing up the engine. Fortunately I was able to quickly find a replacement piston on eBay and then the engine ran without fault.

I thought it odd that the inner workings of the engine seemed to be in better condition than the carburetor.

Later, I began the simple task of bleeding and rebuilding the front forks. I ran into my first snag. The fork screws were sealed with the same gasket glue as the carburetor. And then, to my surprise, the lower springs were missing. I quickly checked online to see if any CB550s came stock without lower springs in their forks. Sure enough the CB550f did. 

Earlier I had noticed the original color of the bike was said to be blue. According to insurance files it had always been blue. I searched online to see if any CB550fours were blue by stock. At first my search would turn up fruitless. 

The rear passenger frame mounts had long since been removed and I hadn’t checked the serial number of the bike. Suddenly I began to fear that my bike wasn’t what I thought it was. 

Grabbing my papers I ran to the garage and scanned the front of the bike. There it was, the number stamped into the front. But I couldn’t see the vin plate which concerned me. Turning the handlebars I saw thick black tape covering half of the front of the frame. More concerning still.

I pealed back the tape to reveal a shiny original vin plate matching the vin stamped on the frame and the vin of the papers. Anyone standing nearby would have heard an audible sigh of relief.

Now I began to wonder about the engine. Fortunately, I had noticed on the website of a European Honda parts supplier a document of all the frame and engine numbers. I compared the number of the engine with frame. The years matched. Then I noticed they also documented the carburetor number as well – which surprised me. 

But as I checked the numbers, the carburetor matched a CB550f, like the forks. Another story emerged. Clearly the forks and carburetor were most likely from the same bike and for whatever reason had replaced the original ones on this bike.

That would explain why the motor seemed in better shape than the carbs. And why I couldn’t find any traces of that gasket glue anywhere else on the bike or engine.

But again I wondered about the color. I knew a CB550f came in blue. Perhaps that was the confusion. But no, the fuel tank was a different shape, rather than having the classic styling with the chrome lid, the CB550f was a more modern shape and had a hidden cap. Secondly, while the frame is nearly identical between the bikes, the mounting points are not. And the CB550f side panels didn’t fit the my frame.

Then by happenstance I stumbled upon a 7 year old video on Youtube of an original blue CB550. It appeared to be the same year as my own. Curious, I went back to the garage and examined my parts. The side cover was cracked and beneath layers of primer and repaints, there as clear as day was a metallic blue. I flipped over my fuel tank as well, and sure enough I could see metallic blue overspray. So definitely the original tank. I did also spot green overspray as well. Perhaps there was an option to custom paint the bike when purchasing it? Or possibly they swapped a cb500 tank and side panels when purchasing the bike? Perhaps someone reading this would know if that is something that was done in the 70s.  

The bike also had a blue face on the odometer gauge with miles matching the papers. Every reference of the bike I can find in bike reviews say the gauges were green. Now I know that my odometer could have easily been changed. So I did some more research on forums, classifieds and Youtube and have since found many 1974/75 cb550s with blue gauges. So again, an unlikely surprise, but it looks to be original to the bike. 

Remember how the tank was badly dented? Well, the story continues. Excited to get into things I immediately began giving the old beast a thorough cleaning. There was dirt everywhere with sand and grit found in every crevice of the engine body.

The bike had been given an intentionally “rustic” paint job for the movie. Where black was painted over silver and then sanded back to reveal the silver in spots. Again, apparently to serve the look of the film. But, despite soap being thrown in its direction the bike still looked dirty after each wash. So a quick trip to my local auto paints store and I returned with high quality black paint for rims. Something that would endure the elements until I would be able to powder coat it down the road.

Well, removing the gas tank revealed a very silver frame indeed. All the hardware such as the battery holder and metal clips were also painted in silver. And the quality was too good to fit the work of the movie look. This had been done before.

The more I investigated the frame and paint the more I was impressed with the workmanship. Someone at some point in its history cared for this bike.

But the cleaning revealed something else too. I noticed some dents on the side of the engine fins. But as the wax was removed the dents turned into chips and cracks. This engine had been through war. The majority of the wear was on the same side where the gas tank had most of its dents.

Had someone used this as an enduro bike? It’s possible.

In many ways, rediscovering an old bike is like unearthing an archeological site. One must rely on the remnants of clues to share the stories long forgotten or untold.

Yet it’s these discoveries that hint to the story and soul of the bike. The peculiarities of the engine. The way it sits on the road. And the charm of its character. Much like an old friend. Battered, bruised but no worse for wear.

And also, much like an old friend. Occasionally they share stories that almost seem too interesting to be true. Yet they are.

Many movies are filmed in the area I live. Mostly small production indie films. Some of my friends are filmmakers. So when Tom remarked that this bike was used on set it didn’t grab my attention. That is, until I began discovering more about the peculiar hints of history that this bike seemed to have. An unlikely original paint color. An unlikely pairing of forks and carburetor. An unlikely speedometer. And even an unlikely turn of events – from the pride of someone’s garage to become what appears to be an enduro to then appear on a film set. All of which was unlikely. But evidence suggested otherwise.

And like all nagging thoughts it asked to be investigated.

It turns out it was in a movie, titled Endless. The movie was released in 2020. And stared Nicholas Hamilton (from IT) Alexandra Shipp (Storm on X-Men).

And surprise surprise, the bike is featured on the cover of the film. 

Alexandra Shipp, Nicholas Hamilton, and the Honda CB550 staring in Endless

Now I know that the bike was in a movie. I know that it was painted blue. I also know that it has a CB550f fork and carburetor. And I know that it was owned by a chef at some point. Tom told me. But I don’t know that it was used as a dirt tracker or that it was stored in a garage. I only have the clues. But isn’t that what great stories are. Just enough to guide you along and just enough to let your mind wonder.

My humble CB550 in a scene from Endless
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Tuning a Honda CB550 carburetor with pods

Here’s how I tuned my 1974 Honda CB550 motorcycle with pods.

My bike came with pods when I purchased it. I will share the full story in another post for those who are interested. And here’s the post on the build. But in short, the choke didn’t work. The carburetor was a mess. One of the carb cylinders was bent and jammed with a missing needle. Some cylinders were beyond repair. Glue was in the carbs. And it was leaking fuel. If I can make this bike run well with pods, anyone can make their bike run nice.

Step 1: Clean and rebuild the carbs.

I disassembled and cleaned every nook and cranny of the carbs. It’s an easier job than you may expect. I had 4 sets of containers. 1 for each carb. And took notes and photos as I went. And noted the number of turns each screw was set to. Which made it very easy to reassemble everything.

Step 2. New spark plugs

Step 3: Tension cam chain

Step 4: Set valve clearance

Step 5: Set timing

Step 6: Vacuum sync carbs

Vacuum Syncing Carbs
Vacuum Syncing Carbs on CB 550

When that is done. You are ready to tune the carbs for your pods.

Here’s the settings that are working for me

Set the carb bowl float heights to the stock 22mm

Size 115 main jets. For reference, I live at 1150ft elevation.

Size 42 slow jets (pilot jet)

Raise the sliding needle by moving the clip to the second lowest position. (Opens the needle)

Fuel/air mixture screw is set at 3/4 turns out. Stock is 2 turns out.

Here’s the settings explained

I set the carb bowl float height to the stock height to stop fuel overflowing. And to get a baseline across all carbs.

The main jets effects the amount of fuel you have at the top end. It was running lean. So upping to 115 solved that.

The slow jets effects the low end and idle. If it’s too rich at the low end you need a smaller slow jet. And vice versa.

The sliding needle effects the middle range of power. The more raised the needle the more fuel is being pulled from the main jet in the carbs. I have 4 into 1 pipes with a small muffler. Which increases the air flow. (Again it’s what the bike came with). By raising the needle the bike gets a richer mixture. Solving the “bog” feeling (too lean) when opening the throttle. If you’re sputtering and sluggish when opening the throttle (meaning too rich), then you will want to lower the needle. Another way of checking. If you hold your throttle at mid point and revs climb and run away, that’s lean. If your revs dip or sputter, that’s lean.

The fuel/air mixture screw was the final adjustment I needed to do. It fine tunes the throttle responsiveness and the idle on the low end. To find the setting that is right for you, warm up the engine, then give a bit of throttle and let the revs settle down. Adjust the screws 1/4 turn at a time. Turning the screw clockwise (inwards) enriches the mixture. Outwards leans the mixture. Blip the throttle and let the revs settle down after each adjustment. If it takes too long to settle down to idle then it’s too lean. If you hear backfiring then it’s too lean. If it sputters with throttle or dips below ideal idling (or just die) when settling down, then it’s too rich. Make adjustments to the screws accordingly. When you get the sound you’re happy with (Not lean, not too rich) that’s your spot. Make a note of how many turns you’ve set it to, so you can remember later.

Troubleshooting

If bike is running too lean/rich at idle to 15% throttle? It’s your pilot jet.

If bike is running too lean/rich at the top end? Hearing tinging, clanging, or overheating at full throttle? It’s your main jet.

If bike is sputtering/dying or bogging when giving a little throttle (20-70% throttle). It’s your main needle height.

If bike is backfiring. Adjust your fuel mixture screw.

Final note. Always err on the side of being too rich. A lean condition can be the kiss of death for a motor.

Thanks for checking this out. It’s been an enjoyable and rewarding project.