Topic: The Rebuild - A 550 Tale

[cabrala]

Some may have caught the "New England Fall Ride" thread a week or so ago that detailed this 1977 CB550's perilous fall from glory. Well, I've migrated over into the project shop for the rebuild. In the hopes of preserving a few minutes of your lives, I'll save the full backstory and just fill you in on some important moments...

The bike has ran great over the past two seasons. It developed a nasty head leak this year and has always had a persistent leak coming from the left-side sprocket cover. My levels were never below normal before a ride and well-maintained during. Over the past few weeks I had problems with the bike stalling out in city traffic, leading me to believe a battery and electrical issue. After this most recent malfunction on the aforementioned Fall ride, I'm thinking they were all somewhat related.

The bike once again cut out on me but allowed a rolling stop. No screeching, no smoke; just no power. At the side of the road, I go for the kicker and it's stuck. My buddy tries the kicker, it's stuck. It's rolled to safety and trailered to my dad's house for future evaluation. Once there, I hit the starter and it fires up but with God-awful squeaks. Shut it and parked it. My intuition is telling me it's an oil delivery failure and the top end is fried.

This is where the rebuild thread takes over and the pretty pictures tell the story.

[cabrala]

Ladies and gentlemen, boys and girls, children of all ages; the moment you have been waiting for...

(Curtain opens. Crowd goes wild with excitement)




I bring you a story about thinking you know what's broken and knowing what is broken.

The legendary Anders, of Blockhead Racing, came to visit (and school) me in my quiet country hometown in Southeastern MA, where we promptly fired up the air compressor, aircraft-grade impact driver and coffee machine. From the get-go we were under the impression that the damage would be located within the top-end, so we made a quick go of pulling the breather and valve cover. The amount of PO orange gasket sealant made me wonder how the bike was running so well and never sucked a loose flap into the cylinders.







We were both surprised that the top end looked so healthy, but it left a big question mark on what the cause of the awful squeaking might be during start up. Onward we forged; off with the head!



Oops, we forgot one screw and took the jugs with us on a good thrust up.



Alas, we find some sticky pistons (1 + 4) and a chip on the sleeve of cylinder 1. In addition, 3 of the 4 pistons are not moving a freely as they should. Again, 1 and 4 are the worst culprits, requiring forceful movement on my behalf, while 3 just seems a lazy. It's not looking so good and I'm not feeling so hot at this point.





Notice the rubbing marks on the following two photographs:







On a side note, what the heck is this blemish behind the oil filter? Looks as though it's been JB-Welded, but Anders and I were both very confused as to why?



Now knowing that the rods, bearings and crankshaft were shot we took to splitting the cases. Anders broke out the impact thing-a-majig and made quick work of 35 year old screws, but we quickly hit a snag when going to disassemble the primary chain and realizing the right tools were not among us. I don't have any good close-ups of the damaged bearing and crankshaft, but I did bring the engine back to Boston so that I can work out of my apartment and will get some detail shots eventually.









The mighty 550 has temporarily fallen and been left naked in the garage...

[cabrala]

Many will now want to know my take on the failure, or perhaps Anders' take as well. We had much time to discuss so I'll leave a hybrid version here.

The leaks I have been finding from the oil pump led me to source a new o-ring for the cover of the pump. If the cover is proud of the pump (even just >.001") there will not be sufficient pressure. It looks as though my cover fit these criteria. Therefore it is believed, in theory, that the oil was sufficiently pressured into the top end but the pump was not exerting enough force to complete the full delivery cycle, in essence starving the bottom end and thus creating this dilemma.

[Killer Canary]

It's good to see that you've retained your sense of humour through it all! Your work will reflect it.

[cabrala]

It's good to see that you've retained your sense of humour through it all! Your work will reflect it.

Appreciate that, Canary. I figure there's no sense in being angry about it when I'm the one choosing 35-40 year old machines.

You wouldn't believe how many people have asked me if I'm ready for a "real" bike, or a "modern" bike, or "something newer". They just don't know style...

[Killer Canary]

I just checked my engine, and that hole behind the oil filter has a Frosst plug pressed into it; the hole is probably a milling byproduct. If yours was leaking, it might've brought the pressure down. Still should've cooked the top end first. Just a thought.

[cabrala]

Anders just contacted me and told me I've acquired a new parts motor. I'll be tearing it down and hopefully salvaging the crankshaft, rods, pistons, cylinders and oil pump. It'll be in town on Saturday and pictures will follow.

[harisuluv]

That o-ring for the oil pump is a real hard one to get a hold of.  There was a guy that had the right size for it, and ordered them, but then didn't want to give out the measurements and wanted to sell them as sort of "intellectual property."  My oil pump cover needs the o-ring, if anyone knows exactly where to find one PM me.  Nice project!

[dave500]

i like to run the oil pump body over wet or dry on flat glass a little,this will close up the wear and allow the rotors to run closer to the cover.

[cabrala]

Haris, I though I had the right one and when that didn't work I was able to grab a square-section o-ring and that's when the thickness issue threw everything off. Recently there was a guy selling a Viton kit for the oil pump; supposedly three case o-rings and a pump cover for $8 plus shipping.

I have some emails back and forth with him. PM me your email address and I'll forward it along.

[cabrala]

i like to run the oil pump body over wet or dry on flat glass a little,this will close up the wear and allow the rotors to run closer to the cover.

Hey Dave, thanks for stopping by.

Are you doing the sand paper to avoid using an o-ring? I haven't delved deep enough into the oil pump yet, as I am still mesmerized by the intricacies of my first split cases, but I'll have to check my pump out and see if I can understand where you are removing some material to tighten things up.

[Stev-o]

Subscribed...

[cabrala]

As promised; a few detail shots of the crankshaft bearings and pistons. It definitely doesn't look pretty but I guess it really shouldn't...


Forgive some of the flash rust below; I was trying out some white vinegar.



Bearing from cylinder #1 rod



Piston from cylinder #1



Piston from cylinder #4

[dave500]

you still use an o ring on the cover crush.

[cabrala]

you still use an o ring on the cover crush.

Now that the engine is in pieces on my porch, no.

I received the bike with orange gasket oozing out of the pump cover. Just recently I opened the pump up to remove the goo and replace the o-ring that was shriveled up. Didn't have the proper o-ring so I did the "make-it-yourself" until I sourced another from a member here (a square-sectioned o-ring from Mc-Master). That thickness pushed my cover proud of the body enough to cause pressure problems.

There was an everlasting oil leak coming from that area, so I figured replacement would solve it...wrong.

[dave500]

ive used 46 x 2 circular section,they come out square after use.

[cabrala]

After work today, I decided to come home and continue clearing out the innards of my split cases in my new "workshop" ...

BEFORE:






AFTER:






The girlfriend's office has become the boyfriend's garage but she's a trooper about it (notice her drafting table is still there!).

So as said above, I am working on removing all parts of the cases that can be removed in order to prep for a thorough cleaning and new paint job.

Starter motor gears


Kick-starter shaft and gearing






Shift drum




Shift forks



Now onto the question of how to remove the shift spindle? It has some ball-bearings on one end and a funny looking connector on the other side. I aired on the side of caution here as to not start forcing things apart. That funny connector also as a very difficult screw; even with the impact driver. Ears are open for "how-to's"...

[dave500]

a tiny clip holds a pin in that centre fork which rides in its worm groove,you might need a magnet to suck the little pin out,or just let it hang upside down for a while and it might drift down and out,,then you can remove the drum,itll push through,,watch you dont distort that little circlip on the end of the kicker shaft,if it pops off when the engines running youll probably lock the rear wheel!!

[cabrala]

a tiny clip holds a pin in that centre fork which rides in its worm groove,you might need a magnet to suck the little pin out,or just let it hang upside down for a while and it might drift down and out,,then you can remove the drum,itll push through,,watch you dont distort that little circlip on the end of the kicker shaft,if it pops off when the engines running youll probably lock the rear wheel!!

I found the pin and removed it, only to put it back in once I couldn't get the screw (in last picture, above post) to dislodge itself. I'll keep going at it and eventually get it.

Your kickstarter warning was almost a day late!

I got frustrated with all the wrong tools, so I decided to give up and leave it for another day. Needle-nose pliers, screw drivers and finger nails (don't recommend) were all actively prying the circlip to no avail. A little research brought me to snap ring pliers so I went and grabbed a pair from the local auto parts store. It's funny how 30 minutes of aggravation can translate into 30 seconds of bliss when you have the right tool.

So, the circlip was saved; not overextended or distorted. I hope the re-install goes just as swimmingly so that I am not experiencing a locked rear wheel. BTW, I hope you don't have first-hand experience of such an event!

[Vreihenmotor6]

do you need an impact driver for that screw? I have one if you do

[cabrala]

do you need an impact driver for that screw? I have one if you do

I have one but it didn't do a damn thing. I'd be willing to try another tool or see if it is just a weak operator. Should I get in touch with you later on? Shoot me an email or PM.  Whatever works.

[Vreihenmotor6]

I'll be home around 6, just give me a ring and I'll stop by, or you can bring it to my place

[dave500]

knock that screw in the undo direction with a small sharp chisel.

[SohRon]

I'll be following this one. Good job of documentation, BTW; pictures really are worth a thousand words! And I dig your new "shop" (wish I had a girlfriend that accommodating!).

[cabrala]

Well I must admit, Ron, you're level of documentation sets the bar for the rest of us so I appreciate the compliment. The girlfriend is quite accommodating especially as I break down the spare motor and give the apartment a nice old-oil musk.

I'll have some updates after the holiday as I split the spare cases and extract the good stuff.