Topic: 1978 CB550K Engine top to bottom overhaul

[eastyork1977]

Starting a long overdue build thread for a buddy's 550K(4) engine. He is currently in the process of building the bike frame up but we've been so busy with the machining and there has been little time to post.
A bit of a pre/post timeline is going to show here as we started the overhaul in the spring.

So to start out, I went and visited the machinist for the bottom end back from cleaning and inspection stage. Factory finish. Everything checks out. Crank wasn't perfect but we had to tap out at that point, budget wise it would be very costly to keep going on the bottom end and I trust my machinist. He's easily got 30 years experience on me.

[eastyork1977]

And presto! Transmission is back in the case and on the desktop.
All new case oil seals, one plug was re-used (unobtainium)

[eastyork1977]

Valves back from machinist looking factory new.
We had to take down 4/1000 off the valve head lower mating surface to correct the warp in the head.
Two bent valves and some piston wear was found upon disassembly.
2 new valve guides were machined custom and pressed. These exhaust valve guides are unobtanium.
All new valves in the head. Aftermarket exhaust, OEM inlets as is available. Exhaust valves are unobtainium.

Cylinder will make an appearance next.

[eastyork1977]

Cylinder: the before pic, ugh...

[eastyork1977]

Cylinder back from machining. In the first picture, you can see the warping where they removed the gasket previously. Surfacing and some decking I believe was needed.

[eastyork1977]

Some more close ups of the jugs.
Will be posting the remaining pics tonight and this week.

[SOHC4 Cafe Racer Fan]

Valves back from machinist looking factory new.
We had to take down 4/1000 off the valve head lower mating surface to correct the warp in the head.
Two bent valves and some piston wear was found upon disassembly.
2 new valve guides were machined custom and pressed. These exhaust valve guides are unobtanium.
All new valves in the head. Aftermarket exhaust, OEM inlets as is available. Exhaust valves are unobtainium.

Cylinder will make an appearance next.

OEM stock valve guides and valves may be hard to find, but better Kibblewhite parts are readily available.

[eastyork1977]

Not in Canada they ain't but cheers guys. Can't beat hand made nickel!

[eastyork1977]

Little bit of the valves in progress. Those keepers are always fun.

[eastyork1977]

Piston check. Some 'light' damage on 1 and 2 lol
Something was definitely bouncing around inside the combustion chamber.

[eastyork1977]

New OEM tensioner parts. A little re-threading was needed to fix up the tensioner adjuster bolt.

[eastyork1977]

The ol' wiggle and shove. Haven't used the piston ring compressors yet. Anyone else find the same?

[SOHC4 Cafe Racer Fan]

The ol' wiggle and shove. Haven't used the piston ring compressors yet. Anyone else find the same?

They are available and they work.

[MRieck]

Cylinder back from machining. In the first picture, you can see the warping where they removed the gasket previously. Surfacing and some decking I believe was needed.

After a million heat cycles every thing needs decking and surfacing.

[eastyork1977]

I've never had to use the compressors, got these on in about 15 min. Shipping from the states is hit and miss and the head was already with the machinist in his skilled hands. He is an ex british salt flat racer. Guy does Nascar and quarter mile drag engines so I go with his word, plus he's a friend.
Not necessarily. After getting about 10 cylinders done in the last few years I've had to deck only 4.

[MRieck]

I've never had to use the compressors, got these on in about 15 min. Shipping from the states is hit and miss and the head was already with the machinist in his skilled hands. He is an ex british salt flat racer. Guy does Nascar and quarter mile drag engines so I go with his word, plus he's a friend.
Not necessarily. After getting about 10 cylinders done in the last few years I've had to deck only 4.

What I find interesting is a head or deck will look OK wih a straight edge but once you take the first pass on the mill you will have high and low spots. The mill is the final word.
 Also...you can use the OEM intake guide on the exhaust side....it's just a little shorter. You can use the 550 guide on CB400F's too but you need to cut them down.

[SOHC4 Cafe Racer Fan]

The mill is the final word.

That sounds like a would be movie line.  I bet you could put a used head on glass and it would look straight as an arrow an still be off.

[eastyork1977]

MRieck That is a good tip, i knew they were slightly different. I leave it to the pros when it comes to pressing and decking. Not my area of expertise.
I heard that marble is best as opposed to glass for surfacing. I've used marble once or twice for surfacing, level laps and quarter rotations of the block.

[eastyork1977]

A peak at the valve guides that were pulled. I knew they were oval but, gah!

All back together. Gotta dust off the top rocker cover and we're gonna drop 'er in this week I believe.
I will have to check on the rolling chassis and how that is coming along... Will post again when we can!

I think most got what I meant by un-obtainium. To me un-obtainium would be discontinued OEM. Aftermarket, NOS and rare good used parts are always kicking around and some of us do have time machines for parts.
Cheers everyone and thanks for the feedback.

[eastyork1977]

The ol' wiggle and shove. Haven't used the piston ring compressors yet. Anyone else find the same?

They are available and they work.

But maybe not in Canada 

calj737 LOL just saw this now 

[eastyork1977]

Shot of the TDC check.
Back with more once we get the roller