Topic: 1975 CB550K Restoration

[HondaAddict]

Since I recently finished restoring a V65 Sabre, I've been looking for another project. I've always had a soft spot for the 1970s Honda SOHCs, especially the fours. I owned a half dozen or so back in the day.

So, this 1975 CB550K followed me home today. The original owner (now in his 80's) has been storing it in a spare bedroom of his house since he last drove it in 1981. Luckily, he had the good sense to look after it.

It's supposed to be all original, right down to the hand grips (I have the original handlebars). There's almost no rust anywhere and the megaphones are pristine.

Unless I find any unpleasant surprises, it should make a good base for a project. It needs lots of TLC, but I'm up for it. I can't start it yet because the carbs need work, but the engine and tranny seem solid. I'll focus on getting it running and rolling, then see how things go from there.

There seems to be lots of friendly and knowledgeable folks on these forums. I'm sure I'll have lots to learn from all of you as I bring this K back to life.

[Stev-o]

Nice find. 

Hate to be the bearer of bad news, but those "megaphones" are not original.

[HondaAddict]

Nice find. 

Hate to be the bearer of bad news, but those "megaphones" are not original.

See how little I know? 

I'll take your word for it. They are stamped HMCB550K HM404. Different year?

I wonder what other surprises I'm in for.

[SOHC4 Cafe Racer Fan]

They look more like 1977-78 CB550K pipes.

That bike has low miles and looks like it's in fair condition.  A great survivor and restoration candidate.

[RAFster122s]

Going to be hard to start without the carbs. Hopefully you have them.
She looks really nice,  I hope you are not planning to cafe a fantastic stock bike.

David

[MickB]

You've scored a gem, it'll come up very nice with some tlc.

[calj737]

I'm curious, were Canadian imported bikes sent with MPH and not KPH gauges?

As for the pipes, regardless, they do look minty and I personally quite like them on that bike. Whether its pristine stock or not, she's a great looking bike!

[Restoration Fan]

As for the pipes, regardless, they do look minty and I personally quite like them on that bike. Whether its pristine stock or not, she's a great looking bike!

+1
Very nice find.
I'm assuming the plan is to keep it stock and just do a restoration?

Ron

[HondaAddict]

I'm curious, were Canadian imported bikes sent with MPH and not KPH gauges?

As for the pipes, regardless, they do look minty and I personally quite like them on that bike. Whether its pristine stock or not, she's a great looking bike!

Thanks!

Canada adopted the metric system in the latter 1970s, so vehicles of this vintage came with MPH gauges.

[HondaAddict]

Going to be hard to start without the carbs. Hopefully you have them.
She looks really nice,  I hope you are not planning to cafe a fantastic stock bike.

David

Thanks! I have the carbs, etc. In fact, I have two sets of spares,

I plan to leave it stock. Or at least as stock as it can be with frankenpipes.

[HondaAddict]

+1
Very nice find.
I'm assuming the plan is to keep it stock and just do a restoration?

Ron

Yep, just a restoration. Maybe there's a cafe project bike in my future, but I couldn't bear to hack up this one. I get why people do customizations, but I die a little inside every time I see a nice vintage bike that's been modded beyond the point of no return.

[SOHC4 Cafe Racer Fan]

Going to be hard to start without the carbs. Hopefully you have them.
She looks really nice,  I hope you are not planning to cafe a fantastic stock bike.

David

Thanks! I have the carbs, etc. In fact, I have two sets of spares,

I plan to leave it stock. Or at least as stock as it can be with frankenpipes.

Those frankenpipes look like they are decent condition.  If you were to return it to the original stock pipes, you'd be spending north of $1600 for reproduction pipes! 

[HondaAddict]

Those frankenpipes look like they are decent condition.  If you were to return it to the original stock pipes, you'd be spending north of $1600 for reproduction pipes!

Yep, that would be much more than I paid for the bike. Looks like I'll need to do a bit of modding to make these pipes fit properly. Oh well, where's the fun if it's easy? 

[HondaAddict]

Well, I expected these carbs would need some work. I was right. I took off the bowls and found all of this goodness.





34 years of sitting will do that. A few weeks of soaking parts in Mopar Combustion Chamber Conditioner, a basic cleaning and a new set of jets were enough to get them operational.



At this stage, the goal is to just get it running, to be sure I have a good base for restoration. I’ll do a complete carb overhaul later.

[HondaAddict]

While the carbs were soaking and the jets were on order, I put some time into a few other basics.

The clutch was siezed as solidly as I’ve ever seen. I pulled it out and got all the plates pulled apart, then gave it a good cleaning. Put it back together and it’s functional again.

Then I put some time into the electrical system. It kept blowing a fuse, so I pulled apart and cleaned all connections. I also found the taillight bulb and socket in this state. No wonder it was popping fuses.





All circuits are good now, except that I need a new signal flasher and the horn isn’t getting power. Minor issues for now.

[HondaAddict]

So, I got the carbs reinstalled and geared up a temporary fuel supply (the tank is a rusty mess and will continue to soak in Evaporust for a while yet).

After a fair bit of cranking and sputtering, it started!

https://www.youtube.com/watch?v=UnO9k4xZjY0

What a nice feeling to bring a machine back to life for the first time in 34 years! That feeling is why I do this for a hobby.

Understandably, it ran rough for a while, but got better with every minute. There was lots of exhaust smoke, which doesn’t worry me. The rings would surely be stuck after so many years and they should loosen up fairly quickly. The smoke was almost gone after about 10 minutes of run time.

It now starts instantly with a touch of the button. My dad (who knew a helluva lot about engines) used to say the best engines start instantly. I'm hoping that rings true this time.

After it was warmed up, I did a compression test. Readings for 1 through 4 were 132, 128, 128 and 130 PSI. I think these are good?

The next step is to get it rolling and take it for a test run. I first have to get some brakes. The front MC and caliper are siezed solid and the frankenpipes interfere with the rear brake lever. I'll fabricate a solution for that later and find a creative way to operate the rear brake for now.

If the transmission shakes out ok (I tried the first few gears in the garage and all seems good so far), I think I’ll be confident that I have a worthy project bike and the real restoration will begin...
 

[mrfish2]

That's a good lookin bike you've got there, and it seems you're on the right track so far. Your compression numbers look fine, depending on the compression gauge you use you'll most anways get lower numbers than what Honda says. The only time to worry would be if they drop close to 100.

Just curious, where did you order your jets from? Some companies don't sell very good quality jets.

[HondaAddict]

That's a good lookin bike you've got there, and it seems you're on the right track so far. Your compression numbers look fine, depending on the compression gauge you use you'll most anways get lower numbers than what Honda says. The only time to worry would be if they drop close to 100.

Just curious, where did you order your jets from? Some companies don't sell very good quality jets.

I ordered OEM jets from my local Honda dealer. The price was as good as the big online sites and they arrived in 5 days.

[HondaAddict]

The gas tank was a mess. The gas left in there for 34 years became a layer of rotten sludge on the floor and there was plenty of rust everywhere else.





I filled it with detergent/water and soaked it for a couple of days to dissolve the sludge. Rinsed it out, put in Evaporust and a few handfuls of new ¼” lock washers. I let it soak for a couple weeks, turning it every day. This is how it came out.







I need to rebuild the petcock. That’s a small chore compared to the tank.

[SOHC4 Cafe Racer Fan]

Wow, the tank sure had some "gravy" in it, but it cleaned up nice.

[calj737]

Make sure the underside of the top is also cleaned and treated. Especially around the filler neck.

[HondaAddict]

Make sure the underside of the top is also cleaned and treated. Especially around the filler neck.

Thanks. I let it soak at all angles over a couple weeks. Helps to have a plugged air vent in the cap.

Looking at it with a mirror, it seems clean all over.

[HondaAddict]

Wow, the tank sure had some "gravy" in it, but it cleaned up nice.

Thanks. It's cool how detergent eats that sludge. Much safer than some of the nasty solvents I've seen recommended elsewhere.

[HondaAddict]

My local Honda motorcycle dealer is located next door to my workplace. I've been shopping online for my next batch of OEM parts and I thought I'd check the pricing with the dealer first. Good idea.

The 7 small parts I need would have cost CAD $155 (incl. shipping) at a big online site (I won’t name it, but it rhymes with Dartzilla). The same parts cost CAD $123 at the dealer, and I'll have them in 5 days. The online site was 25% more than the dealer.

We Canucks get dinged with almost criminal shipping charges (minimum USD $30) plus currency exchange when we buy from the big US online sites. With customs clearance in the middle, I can wait 2 weeks or more for delivery from the online suppliers. And I haven't found a Canadian website that has all the OEM parts.

I'm happy to support the specialty online vendors who sponsor websites like this, but it also feels good to support my local dealer and save a nice chunk of change in the process.

[pipeguy]

Awesome find, congrats!!!!