Topic: Bringing my 1978 CB550k back to life

[Slam]

Hi all. My name is Ray and I live in southern NY. Long story short my dad gave me his 1978 CB550K years ago when I told him I wanted to learn how to ride and it was my first bike. He was a mechanic most of his life and helped me rebuild the carbs (see pic below, no idea what I’m doing, just doing as he said). Then I bought my own bike (2003 VFR800), the CB sat for a bit, and started acting up again. Sadly my dad passed away before he could help be figure it out and it has sat since then, which was about 2015. Just a couple weeks ago I finally brought it over to my house and have it up on a lift. Last I tried to ride it, it would start and idle fine, but start bogging down after it warmed up, couldn’t go faster than 20-30mph even with the throttle pinned. I tried checking all the basics, fuel lines, fuel filter, spark plugs, points, etc. At minimum the carbs need to be rebuilt, and I think at least some portion of the motor needs to be rebuilt due to a fairly obvious oil leak. The master cylinder has a weird gunky substance surrounding it. So, I’m in for a project, and I’m no mechanic myself. I’m handy, I built custom guitars for a while and custom furniture for another few years, but don’t really know where to start with engines and carbs. Hoping between this forum and the YouTube’s, I’ll be able to figure it out! Here are some pics for reference. Thanks and I look forward to posting my progress here.




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[FourUsTry]

Good luck! I've got the same machine (but with stock exhaust) back on the road and running well. Put your questions up here and we'll try to help.


For bogging down I'd check/replace ignition plate with OEM (or at least condensers), do the static points gap and timing, and set the valve clearances for starters. If the coils are original I'd at least test them if you can't replace them but replacing the coils and plug wires if they are original is highly recommended. New plugs properly gapped unless they are low mileage. A new air filter is a cheap way to eliminate air flow issues as a possibility. With you exhaust I'm not sure whether the stock air filter is best but it is tied up with what needles you are running in the carbs (others here can be more helpful on this).


Assuming it is still bogging down at that point you might want to try running some Seafoam type cleaner in the gas and a Seafoam carb bowl soak overnight treatments before resorting to pulling the carbs. And then leaving fresh gas in the bowls (you aren't trying to run on old gas I hope) overnight can plump out the float needle seals and stop the leaking (worked for me). Also tapping on the carbs and bowls may free up stuck float needles. You might also want to do a clear tube float level check, idle screw adjustment, and carb sync. Check for vacuum leaks on the carb boots by spraying a little starter fluid around the collars while it is running to see if the RPMs go up. If none of that helps and you are sure the spark is good and fuel is getting to all the carbs then you might have to pull them and repeat the rebuilt (ugh!).


Have "fun"!

[SOHC4 Cafe Racer Fan]

From what you describe, you will need to clean your carburetors (remove bowls, jets, floats, etc., ultrasonically clean them and likely replace gaskets.  Buy genuine Honda parts (shaped not round gaskets).  It goes without saying that your existing gas needs to go. Modern gas has ethanol that starts destabilizing and turning into water and varnish.  When you fill your tank, add a capfull of Seafoam or other fuel stabilizer.

You will also need to rebuild your master cylinder.

You can download the Honda service manual here:  http://manuals.sohc4.net/cb550/
I suggest printing a copy 2-sided and 3-ring binding it for your garage.

[Slam]

Thank you both for the responses! After looking in my profile I was reminded I posted about this in 2015, and included a video. I'll include that video here. Also a side note, my wife had our first child about 5 weeks ago so progress on this project might be slow going 

[LastChancer88]

Great looking bike!  Take your time with the work.  My bike was in a very similar condition to yours and it's important to go slow and do it right.  I would do everything SOHC4 Café Racer Fan said.  You sound very handy so you'll get the hang of it.  Just follow the manual.  I use youtube sometimes to see what the manual is describing but with caution for any advice from home mechanics =)

[Slam]

LastChancer, I definitely plan on taking my time. I have the VFR to ride so I want to make sure I do the 550 right.

Buy genuine Honda parts (shaped not round gaskets).  It goes without saying that your existing gas needs to go.

SOHC4 Cafe Racer Fan - a while back I ordered a carb rebuilt kit from 4-into-1... is that the kind I should avoid and get genuine Honda parts, instead? Thanks for the link to the manual, I actually believe I have an original hard copy but that's a good backup.. I'm sure some pages are missing.

[SOHC4 Cafe Racer Fan]

The 4-into-1 carburetor gaskets are okay.