Topic: Boxes of CB550 parts

[saxamaphone]

Hi guys, yesterday I went to pick up some parts that were advertised as "74 CB550 parts" but the only thing pictured was the engine and the frame.  I didn't know what to expect, but the price was very good.  I've haven't been able to solve why my 550K1 keeps fouling plugs so I thought if I investigate the head and pistons it'd be nice to have some spare parts just in case.

It turned out to be mostly 74 550 stuff with the seemingly random later 550 parts thrown in, plus a Yamaha tripe tree from who knows what.  No handlebars/controls or mufflers unfortunately.  I was told they were going to make a bobber but it didn't end up getting started.

As you can see, there were some boxes full of stuff.  The tank is a 77 or 78 I'm guessing, I'm sure someone will know it.  The carbs are the same as my 75 CB550K1, the engine is a K0 serial, as is the frame.  It came with one side cover from 77 or 78.  There were also air filter parts that I'm missing on my K1 so that made me happy, as well as the metal chain guard that's in good shape.  Mine is black plastic.


Carbs are in good shape on the outside...The wiring I'll have to check out further.  All the bolts, washers and nuts are just loose in the box.




Gauges are in good shape.  My tach keeps sticking and won't go over 3K rpm so hopefully this one works.  I had mine apart last year and I thought I had fixed it but it's started doing the same thing again.




The engine will be interesting to check out.  This is pretty disconcerting though.  Looks like someone was trying to get a stuck valve cover off...and the sheared top is inside!  Tips on getting that one off?




I'm guessing the frame is useless but I'd love some feedback.  They cut off the hoop at the back and also here in the picture below.  The PO said he realized he can't weld...





Here's the frame plate with 12/74 as the build date.  It also says it was an F:


Someone added a new place for the keyed ignition.


The intake boots are all cracked unfortunately.  Almost looks like someone tried to cut them off.


Mine doesn't have this rubber piece for the kickstand.  Looks practically new.


Here's one of the boxes.  As you can see, a mix of later model 550 stuff and K0.




And who knows what Yamaha this is from or if it can be used?

[Mo]

lol "he realized he can't weld"....

Its as if there was no way of knowing that ahead of time...

[saxamaphone]

I know.  I'm very aware I can't weld  .  I wonder if this frame can be used for anything, maybe a cafe racer?

[Bankerdanny]

I would guess that the frame is a combo of two different ones. Someone had a damaged frame with title and a good frame without, so cut off the head tubes and combined the headtube with the good VIN to the undamaged frame. As is I would say that frame is scrap.

To get the sheared adjuster cap off get a  bolt with flanged head in the same size as the undamaged caps (14MM? I don't recall) and turn it upside down and fit it into the hole. Then use a double nut on the threaded side so you can use your wrench to loosen the cap.

[dave500]

with a sharp chisel knock that cap in the undo direction,itll come off easy,good score man!bit like a lucky dip?

[MoMo]

lol "he realized he can't weld"....

Its as if there was no way of knowing that ahead of time...

What do you mean ?  that is an awesome weld job    Guaranteed to separate first bump..Larry

[Bankerdanny]

To get the sheared adjuster cap off get a  bolt with flanged head in the same size as the undamaged caps (14MM? I don't recall) and turn it upside down and fit it into the hole. Then use a double nut on the threaded side so you can use your wrench to loosen the cap.

with a sharp chisel knock that cap in the undo direction,itll come off easy,good score man!bit like a lucky dip?

Come on Dave, that's way osimple, my way would be much more fun.

[Lostboy Steve]

Holy Christ. What was done to that frame should be considered a crime to humanity and should be punishable by castration so as to end the lineage of that individual. lol Anyway, the guy who welded it must have though he was going to "bob" it around. Seems to me like he's doing his fellow man a service if on the first test-ride the front breaks off and he earns himself a darwin award. Too bad that never came to pass. All the other stuff looks nice. The inside of the tank looks very clean so that a giant plus.

[saxamaphone]

I'll have to keep my eye out for a frame now.  I just took off all the valve caps and removed all the head cover bolts (with no strips! Just came in to check and make sure I've got all the bolts off I need to in order to get the head off.  So far the inside of the head is looking clean and it turns over with a wrench on the crank.  They valve clearances are all extremely loose.  I doubt I'm lucky enough that this engine has good compression and  could just run with a little tweaking.

The tank is pretty clean inside surprisingly.  Any guesses on the year?  Aren't those gas cap types 77 or 78? 

Instead of 544cc written on the front of the engine it's just got Honda.  Did the K0's have that?

[calj737]

Sax - the frame is usable, but will obviously require some corrective welding. The headstock may have been altered to change the rake/trail. The rear hoop is easy to restore. Original tubing from Honda is very thin and not particularly rigid in their welds. Any competent welder can re-cut, weld and fashion a new hoop for you.

If the frame has a title, repair it. Pend the money to have it done professionally, but do it. While they are at it, they can re-weld the front engine cage where the ends are sleeved. Bear in mind, just because welds aren't pretty doesn't make them weak. I've seen pretty welds fail and many ugly welds endure. Could just be that he didn't have the means or personality to grind the welds. After all, a welded surface is fusing two pieces into a single, so beauty is only subjective to the strength.

If you replace the hoop, use new Cro-moly tubing, it's lighter weight and you can use much thicker walled tubing. Same for the back bone should that need to cut out and replaced. If I recall correctly, the factory tube was 0.16 thickness. Paper thin by modern standards. Use 0.83 tubing that's DOM and the integrity is FAR better than original.

[saxamaphone]

Wow Calj, that's some great information.  My cousin is a professional welder who is down your way quite often working on a pipeline I believe.  Not sure.  He's a Harley guy but if I can get him while he's up here maybe he'd give me the family rate .

I decided from the look of the engine I mights as well take it apart.  I've never done a 550 engine.  I just finished rebuilding my CB450's engine so I figured "how different can it be"?   They actually seem a bit easier to me than the 450.  Of course I haven't gotten into the crankcase yet.  The 550s seem to come with waaaaayy more spiders.

Here's how it looks:





The valve faces are pretty rough but I guess I'll take them out and get someone to measure them.  I unfortunately don't have a micrometer.




The tops of the pistons have some carbon build up.








The pistons are very clean.  Almost no marking.  No stuck or broken rings either.


I took this shot to get the 374 in it but when I look at the photo now, that looks like a crack in that piston.  I'll go back and check the piston in a bit.


After testing and seeing this cam chain tensioner I realize the one on my 550 is pretty hooped.  This one is great.


The cylinders actually look really good.  There's no marks in any of them that you can see or feel, only a bit of discolouration here and there.  I really wish I had an inside micrometer, then I'd just know if they're in spec.




Over all I'm pretty impressed with how clean things are inside.  The camshaft seems to have little to no wear on it.  Once I get things measured I'll have a better idea.

[MoMo]

Looks like normal wear and tear, you may be very lucky ...Larry

[saxamaphone]

Just took the piston I thought was cracked off.  The pin looks very good and there isn't a crack, it was just some old oil I guess since it wiped away.  The pistons really are in good shape.

On the other side of the wrist pin from the number 374 is another number.  Two of the pistons it's 3 and the other two are 2 and 4.  I don't see an oversize number so I guess they are original bore size.  Anyone know what the other numbers mean?  Something to do with manufacturing?

Maybe I should have put some oil in this and fired it up? Just kidding.  I'm glad to get a chance to check out the insides.  I'll probably do the same with the engine on my 550k1 since it's fouling plugs and I've tried everything but look into the head and check the rings.

[saxamaphone]

Just reading through the manual and I realized it might not have been necessary to break the cam chain.  I have an extra master link around though.

When tearing the engine down to the crank case do you guys generally leave the cam chain whole?  I did it without realizing you might not need to since it's necessary on Cb450s.

[MoMo]

Not necessary to break the chain and not a bad idea to replace if you have the motor totally torn down

[saxamaphone]

Thanks Momo.  I'm going to pick a cam chain and the pin clips up from the Honda shop here.  They're surprisingly good with prices at this one and they have an amazing collection of old Hondas I like to check out.

Any other seals I should get for good measure?  I'll need a new base gasket and head gasket as well.

[calj737]

When you re-assemble the engine, fill it with "break-in oil" from a company like Royal Purple. It will add many beneficial additives to the engine seals and surfaces and prolong the life of the engine. Run it for about 500km then drain it and change the filter. You will thank yourself after many miles... Rings and valve seal/guides will seat better and you should end up with better compression and less likelihood of blow-by.

[MoMo]

Seals are relatively inexpensive so since the motor will be apart.......................may as well replace them all...Larry

[MiGhost]

Save yourself some $$$ of buying individual gaskets. Just get the complete set. You will use the majority of them.

The trap door tank was the 77-78.

The relocated ignition switch looks like possibly a CB650 top tree. The Yammy top tree looks like an R1-R6.

You will likely find some resistant about getting that steering neck welded by a pro due to liability issues. It looks like approx 3/4" was hacked out of the neck. You might have problems getting a tank to sit properly again without custom mounts.

IMO. Cut that neck free. Get some DOM tubing. Goose neck\Rake the frame to build a pro street.