Topic: 1975 CB550 - What have I got myself into?

[aliphian]

One more good thing to do is a compression test. (did someone already say that). I'm not sure what it should be on the 550 but I'm sure TT could say.

I got a compression tester from harbor freight a while back. I am sure it is made for cars. I will have to do some research on that. Hopefully whatever bogus numbers it does register will at least be consistent among all cylinders.

[TwoTired]

One more good thing to do is a compression test. (did someone already say that). I'm not sure what it should be on the 550 but I'm sure TT could say.

I got a compression tester from harbor freight a while back. I am sure it is made for cars. I will have to do some research on that. Hopefully whatever bogus numbers it does register will at least be consistent among all cylinders.

You are on the right track.
There is an entry about this in the engine FAQ.
If you use the same test gauge apparatus Honda did, then it's 170 psi. (Listed in Chapter 3 of the Honda Shop manual).  I've never seen a reading that high on any of my Hondas with the gauge I got from the Auto parts store, though.   I don't care, as long they all read within 10% of each other.

Cheers,

[lucky]

I've had (have  ) a lot of these bikes so here is my take on what you've acquired.

I believe your bike began life as a 1975 CB550K model.  Frame, tank, and foot pegs are correct or that model.

The exhaust is from an F model, and I expect you will have problems with the brake arm and kick start lever interference.  I've yet to see any successful graft of the F exhaust system onto a K model.  You have less headaches with that interference and fitment using almost any other muffler system.

Looks like the seat is also from an F model which is why it fits so badly on the bike.

Someone, has tossed the air filter box and put on a K&N single filter in its place.  It needs a cleaning and re-oiling, at least.  But, it gives no protection from rain or road grunge, so best to learn how to clean it as it will need that frequently.

The lack of center stand (it's been removed) means you are going to need a lift of some kind during resurrection.

Since you oiled the front brake pads, you will now have to replace them.  FYI , the next time you encounter a frozen front caliper just loosen the two caliper bolts, and you can probably reuse uncontaminated pads.

Shouldn't take too much to make that bike streetable.  Brake rebuilds, tires battery, fluids, fork seals and cleaning.  Get a K model seat from a 72-73 CB500 or 74-76 Cb550 K.  And get an exhaust for those years, you should be good to go.
Lastly, clean and polish the fuse clips to prevent a fuse box melt down.  And to prevent nagging electrical issues/stoppages, clean all the connectors in the wiring.  Don't ever, I mean ever, connect a battery with reverse polarity.  Smoke flame and damage WILL occur.
Also, don't take off the cam cover without paying special attention to the shop manual, or risk bending valves.
Use 0000 steel wool on the chrome bits.  You'll be surprised how much better it will look.

I caution the use of a straight wall plug socket on the spark plugs, particularly during installation.  The tool kit socket was bell shaped to clear the obstructions in the access tunnel.  A straight wall tends to angle the plug during install, cross threading the spark plugs, and steel is tougher than the aluminum head.

Cheers,

Edit: punctuation and improper pronouns.

WOW!!! TooTired that was good!

[Flying J]

What a pile of crap! Ill come by and help you out.

[aliphian]

What a pile of crap! Ill come by and help you out.

Haha! I would greatly appreciate that!

[Rob69]

Hello everybody. I have been searching for a couple of years for a CB550. Problem was, I am cheap, and I didn't want to spend very much. This brought my options to ZERO. I toyed with the idea of getting a 350 for a while and I had a couple of them pop up on Craigslist only to be gone within minutes. So last week I was talking to my cousin about this and he said "I think I have one of those in my backyard." So I went over to his place and I found a CB550 that had been sitting next to his garage for the past 6 years. I had to reclaim it from the Earth. This thing is covered in vines and spiders.

The good part is that I got it for FREE and he claims it was running when it was parked there (by another cousin).

My plan is to make it streetable. I don't want to start off overly ambitious and never finish it.

I am going to need a LOT of help and direction from this community. I have basically no experience with anything like this. I have ridden before, I've owned a 1989 FZR600 and a 2003 R6 but I have never done much work on bikes.

Okay, picture time. I have noticed there are a lot of great photographers on this site, I'm not one of them.

You may notice on the mirror there are vines wrapped completely around it!

I saved one of these last year for a guy who hadn't had it running in over 15 years. It was perhaps worse than yours, but after 8 months, $2,000 (it needed everything mechanically speaking), and a lot of work, it ran like a champ.

1974 Honda CB550K.

[crysis]

Only thing I heard about throwing your numbers off was the length of hose that the tester has. Seems odd that if that actually matters but any "compression " tester should work I think and yeah as TT said I wouldn't hope for a stock reading but I've heard more than not that most of these bikes get a decent reading...usually...I'm kinda wanting to do a 550 too now. Focus..must finish the 750

One more good thing to do is a compression test. (did someone already say that). I'm not sure what it should be on the 550 but I'm sure TT could say.

I got a compression tester from harbor freight a while back. I am sure it is made for cars. I will have to do some research on that. Hopefully whatever bogus numbers it does register will at least be consistent among all cylinders.

You are on the right track.
There is an entry about this in the engine FAQ.
If you use the same test gauge apparatus Honda did, then it's 170 psi. (Listed in Chapter 3 of the Honda Shop manual).  I've never seen a reading that high on any of my Hondas with the gauge I got from the Auto parts store, though.   I don't care, as long they all read within 10% of each other.

Cheers,

[Flying J]

With my harbor freight tester i have found that above 125 is rideable.

I did test a cd175 today and he came out at 90! but both cylinders were 90.

[aliphian]

So my carb rebuild kits should be waiting for me when I get off work. I'm kinda scared to get in there. Wish me luck!

[Stev-o]

Welcome and good luck. Looks like you are off o a good start. If you are still waiting for parts, there is something you can do that won't cost much: clean clean clean every part on the bike.

[geminimotors]

Amen, SteveO. Cleaning and polishing is nearly free and brings immediate results. It's good medicine when you're thwarted by other complications or mysteries.
 I dunno if it applies to you, but here's an old gem I've been thinking about:
 "If I get hung up with maybe a busted knuckle or a busted stud, I feel my tools, like art objects or lovely feelies until the rage subsides and sense and love return." -John Muir