Author Topic: 78 CB 550K motor rebuild (Read 61454 times)

AlekStooge · « **Reply #225 on:** December 18, 2016, 10:34:53 AM »

Cal!

you bored my cylinders for 59mm pistons. You had the pistons on hand. Did you forget?

Yes they are .50 overbore pistons.

I think I'm just going crazy or I'm missing something/measuring something wrong. Clymer's says replace pistons if the side clearance is 0.007 for top ring and 0.006 for second and bottom. My largest feeler gauge 0.026 feels loose on all of them. I don't know if I have the wrong pistons or what?

calj737 · « **Reply #226 on:** December 18, 2016, 12:48:43 PM »

I do remember. I also remember having the rings checked for end gap and they were completely fine. Some(one(thing)) is wrong...

AlekStooge · « **Reply #227 on:** December 18, 2016, 03:09:50 PM »

Alright, well I trust you more than myself. I measured two inches below from the top like you said, as well as a little bit higher.

calj737 · « **Reply #228 on:** December 18, 2016, 06:09:44 PM »

Got a picture of the ring in the bore with a feeler gauge?

AlekStooge · « **Reply #229 on:** December 18, 2016, 11:12:49 PM »

That's the .010

calj737 · « **Reply #230 on:** December 19, 2016, 02:16:52 AM »

Better file them... Its been so long since those were bored and sent off, I don't recall what the machinist said. I'd inquire with him, but I'm sure he won't recall either. $:-\$

AlekStooge · « **Reply #231 on:** December 27, 2016, 04:17:10 PM »

I got a Honda manual for myself. It looks like the piston ring end gap should be between 0.005-0.013 Wouldn't it make sense to file less off and increase the longevity of my rings than to file to 0.010-0.012?

How are these tolerances determined, just curious?

RAFster122s · « **Reply #232 on:** December 28, 2016, 12:22:27 AM »

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 · « **Reply #233 on:** December 28, 2016, 09:06:51 AM »

Quote from: RAF122S on December 28, 2016, 12:22:27 AM

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 · « **Reply #234 on:** December 28, 2016, 09:17:21 AM »

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 · « **Reply #235 on:** December 28, 2016, 02:05:19 PM »

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

tshrey · « **Reply #236 on:** January 01, 2017, 01:47:57 PM »

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 · « **Reply #237 on:** January 02, 2017, 08:32:14 PM »

Quote from: AlekStooge on November 13, 2016, 07:14:32 PM

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 · « **Reply #238 on:** January 03, 2017, 07:00:25 AM »

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 · « **Reply #239 on:** January 22, 2017, 12:32:18 AM »

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 · « **Reply #240 on:** January 22, 2017, 01:21:51 PM »

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 · « **Reply #241 on:** January 22, 2017, 04:51:42 PM »

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 · « **Reply #242 on:** January 23, 2017, 10:21:31 PM »

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 · « **Reply #243 on:** January 26, 2017, 07:12:46 PM »

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 · « **Reply #244 on:** January 27, 2017, 11:02:56 PM »

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 · « **Reply #245 on:** January 28, 2017, 12:01:51 AM »

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 · « **Reply #246 on:** January 28, 2017, 07:00:33 AM »

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 · « **Reply #247 on:** January 28, 2017, 07:53:52 AM »

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 · « **Reply #248 on:** January 28, 2017, 09:27:38 AM »

Quote from: AlekStooge on January 28, 2017, 07:00:33 AM

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

Quote from: AlekStooge on January 28, 2017, 07:00:33 AM

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 · « **Reply #249 on:** January 28, 2017, 07:08:13 PM »

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.

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Author Topic: 78 CB 550K motor rebuild (Read 61454 times)