Topic: 78 CB 550K motor rebuild

[RAFster122s]

They have to have enough gap for when heated to operating temps they do not butt up against one another too tightly causing them to score the bore or break a ring.
The ring gap clearance is designed to give them room for that expansion.

[AlekStooge]

They have to have enough gap for when heated to operating temps they do not butt up against one another too tightly causing them to score the bore or break a ring.
The ring gap clearance is designed to give them room for that expansion.

Aha got you. So can I filed it down to closer to 0.005 rather than 0.010? I mean according to the manual it is still within tolerance.

[flatlander]

the instructions that came with your pistons should specify an end gap. i'd use that instead of the honda manual because those were for honda's materials.

[MRieck]

General rule of thumb is .004 gap for every inch of bore

[tshrey]

You ever figure out where those pins came from?  I was replacing the rubber bumpers inside the primary shaft today.  After tapping the gear back down into place I picked up t starter clutch and found two pins laying on my bench.  They were the rollers from inside the starter clutch.

[AlekStooge]

I've looked at everything over again and even bought calipers. I don't see anything that is 4X7 in any of the parts fiches. Really scratching my head here.

http://www.cmsnl.com/honda-cb550k-1978-usa_model7222/partslist/

Number 24 is missing so I'll have to order it. http://www.cmsnl.com/honda-cb550k-1978-usa_model7222/partslist/E++14.html#results

You have to take a circlip off to get to where that part sits. I only just recently took that apart and didn't see it sitting in there. No idea how that could happen.

Unless that pin is the same size as above then it is not it. I believe I looked at that part and thought it was #13 for a while. http://www.cmsnl.com/honda-cb550k-1978-usa_model7222/partslist/E++14.html#results If I remember correctly those where really held down deep in there and there was no way they could easily fall out. I appreciate your input but I don't think that is it. Measure it and let me know.

[tshrey]

No, they're definitely smaller diameter than that.

One that size did fall out when I was putting things together but now I don't remember where it came from.

[AlekStooge]

I got the rings on for my last piston. Thanks to Cal for coating the piston and getting it to me pretty quickly. I fitted the rings slightly larger than Brent's minimum recommendations. Tomorrow I will drop the jugs.

Even though I used oil, some of the pistons have light scratches above the top ring surface area from installation of the rings. What can I use to polished them out. Steel wool?

[AlekStooge]

I noticed my Wisecos have two grooves on each side for the wrist pin clip but only come with one for each side what's the inner groove for?

What's the best way to install these clips by hand or using a tool?

[bwaller]

The inner groove must be a pin oiling solution. Use needle nose pliers to install, but be certain they are completely seated. Install # 2 & 3 pistons first, use rags to cover openings into the crankcase.....in case there are run-away clips.

[AlekStooge]

My needle nose pliers are too thick to fit into the bore. I ended up shooting a clip across the room and that was the end of that. Luckily I had a spare set. I eventually got the clip in by getting one end in the groove then pushing in little by little and using a straight pick to help. I did not scratch the skirt. Not exactly fun to do, but ended up easier than I thought when I started.

I tried getting my rings staggered 120 degrees apart and none at the wrist pin or 90 degrees away from it, that seems like the way to do it. I didn't use a ring compressor, I tried wiggling little by little moving the jugs over the exhaust side first then the intake side one ring at a time as I was told starting with cylinders 2 and 3. Gave up for tonight...

[AlekStooge]

Got my block on. I had an old timer help me out. He said I was being too meticulous and staggering the rings is not so necessary as long as they are not lined up and the oil ring does not overlap.


That night he was restoring a 1959 YDS 1. He has done one before and turned out beautiful.
Here's a photo of that Yamaha model.
https://upload.wikimedia.org/wikipedia/commons/c/ca/Yamaha_Sports_250S_YDS-1.jpg

As he was sliding his side of the block in, he must have accidental tore my base gasket. I later noticed once we had all the rings in. I thought I had to start over but after questioning him for a few minutes he assured me it will be fine because there is not too much PSI going through that part of the engine like there is in the head. He ended up putting a patch of hi temp gasket maker. Based off seeing him work on his Yamaha and seeing his other bikes I trust him. What do you think? 

[AlekStooge]

Where does 5,16 and 17 go? From the fiche it looks like they are supposed thread into the shaft but that's not it. Can't see anything in the head cover or head where it'll go. I also got to find 16 and 17 I didn't put them in the same bag as 5, I dunno why...

http://www.cmsnl.com/honda-cb550k-1978-usa_model7222/partslist/E++04.html#results

[flatlander]

5 keeps the rocker shaft from turning. are you sure you did have it at all? earlier covers didn't use them.
16 and 17 are on the outside of the cover and threaded on to 5 to keep it in place.

in the picture, the holes closest to the middle, that's where the threads of 5 poke out.
you first install the rockers and shafts, then turn the shaft (there's a screwdriver slot at its outside end) so that 5 fits through.

[AlekStooge]

Is this it?


Don't you mean the threaded side is facing the outside, isn't it there to be meant to be used as a puller and the slotted end is on the inside.

Here's what I mean

[bwaller]

Pushed through from the inside, nut on top Those 6mm flat washers are larger OD and thicker than usual. Don't overtighten them and crack the cover. I often use a nylock nut instead.

[flatlander]

Is this it?

no, the "inside" holes, the ones closer to the middle of the cover.
once you have the shafts installed there's really only one place where they can go to lock them. and indeed, you push them through from the bottom side of the cover

Here's what I mean

yes, like that.

now push the shafts in and install the rockers. then push those locks things through from the inside/bottom side.

[AlekStooge]

Thanks I got it to fit thought the outside holes not the inside ones. They were to small in diameter and the shaft does not go pass them. I send you a picture one I have it together.

I think I'll be able to get those nuts and washers at the hard ware store. I'm guessing the nuts are 1.0 in pitch.

[flatlander]

the whole pin does not go through the insides holes. you only need the thread to get the nuts on and pull them up, so that the flat wedge on them keeps the shaft from turning.
bummer i have no pictures of this, it's much easier in practice than it sounds.

[AlekStooge]

6mmx1.0 pitch, Alek. All 6mm bolts/screws on your bike are 1.0 pitch. All 8mm are 1.25 pitch.

I thought so. Thanks

Flatlander: I believe you are mistaken.


If you look at the outside hole on the right you see the opening where the shaft passes through.


If you look at the inside hole there is no opening and the outside hole below it fits the part.

[flatlander]

ok i might not remember correctly. just install the shafts and rockers and it will all fall into place. there is only one place where these keeper things (or what you call them) can go where it makes sense. i think you're over thinking it

[AlekStooge]

ok i might not remember correctly. just install the shafts and rockers and it will all fall into place. there is only one place where these keeper things (or what you call them) can go where it makes sense. i think you're over thinking it

No worries I got it now.

[AlekStooge]

Put MLS in dry right?

[AlekStooge]

Yeah I'll put it in dry.

http://forums.sohc4.net/index.php?topic=102783.0

Why is there a hole between the stud and the O-ring? I don't see anything on the head that fits into there.



I was reading ahead in my owners manual and it says there is an aluminum washer and a copper washer on each side of the bolt for the camshaft side covers. I don't remember any copper washers. Why the different metals?

[AlekStooge]

When I matched my part numbers, the dowel pins are rather large and fit over the front studs. They fit the bottom side of the head and slide over the studs. I thought they would be in the center if the block and head where the o rings go. I'll post a picture later.