Author Topic: 78 CB 550K motor rebuild (Read 60677 times)

AlekStooge · « **Reply #350 on:** April 09, 2017, 02:42:16 PM »

I took the cover off here is the piston 1 at TDC. As you see the cam notch is lined up.

DaveBarbier · « **Reply #351 on:** April 09, 2017, 03:15:16 PM »

Assuming that 1/4 is actually at TDC this all seems ok to me, but I'm no expert. The notch is a little lower on the head surface but that's normal in my experience. It's not going to line up perfectly.

I honestly don't know. I wish I had an answer for you. It seems like you're doing everything right, but the tappets still end up tight when they shouldn't be. Sorry for asking to remove the cover again. I'd put the cover back on and work at it again. Rubber bands and tapet adjuster screws backed out.

Your modded cover doesn't have any weirdness going on with it, right? I assume you'd mention that if there was.

AlekStooge · « **Reply #352 on:** April 09, 2017, 03:22:04 PM »

No weirdness to my knowledge. You are right about getting the notch perfectly even, you can't get it perfect with having the sprocket bolts off center. Does it matter which side of the head the cam notch is on? Maybe that's it.

calj737 · « **Reply #353 on:** April 09, 2017, 04:33:20 PM »

It does not matter.

And you have now confirmed by measurement thru the plug hole that #1/4 are TDC?

DaveBarbier · « **Reply #354 on:** May 14, 2017, 04:33:43 PM »

Hey Alek, any update on this motor?

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AlekStooge · « **Reply #355 on:** July 15, 2017, 06:56:34 AM »

Alright cam is degreed in and ignition plate is set with TDC.

It looks like I missed an O ring in the transmission it is hard to see so I missed it. Number 40.https://www.cmsnl.com/honda-cb550k-1978-usa_model7222/partslist/E++15.html#results

Should I open the cases back up. Will I have to replace seals again?

Also I think this shift seal could be put in with the cases together, I don't remember... looks like that is the only way to do it.

DaveBarbier · « **Reply #356 on:** July 15, 2017, 03:56:22 PM »

The shifter shaft seal can be put in any time. It's easiest if the shift shaft is removed, though. If there's no oil in the motor yet, just remove the clutch cover and pull out the shift shaft a little until you can just pop the seal in. Or, if you don't want to do that, cover the shift shaft splines in electrical tape and carefully slide the seal onto it and tap it in place with something that fits the OD of the seal that will still slide down the shaft.

As for the o-ring, I didn't know there was an o-ring in the output shaft right there. I can't even really tell where it's pointing to or what the purpose is. Someone else will have to chime in about that.

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DaveBarbier · « **Reply #357 on:** July 15, 2017, 03:57:20 PM »

How do you know you missed it? Did you disassemble the tranny at all? To my eyes it looks like it's part of the tranny assembly...?

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AlekStooge · « **Reply #358 on:** July 15, 2017, 05:39:02 PM »

Yes I disassembled the trans. I was going through my remaining oil seals and o rings because my covers are not on yet and that was one of them left over. It is a part of the trans. I could see why I missed it. That is the only place that O ring goes. O well I guess it won't take me that long to do I'm just worried about the seals already installed.

DaveBarbier · « **Reply #359 on:** July 15, 2017, 09:17:11 PM »

I would bet the seals would be fine. It's not like they've been in place too long or gone through any heat cycles.

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AlekStooge · « **Reply #360 on:** July 19, 2017, 01:53:17 AM »

I tore the cases apart. Long story short. The case slightly moved forward.

The damage doesn't look too bad and the lip isn't damaged. I happen to have an extra of that crank seal! However to take it off I would need to take my cam sprocket off, which would require me to flip the engine up right with the bottom case off. I'd have to re-degree the cam after that. Unless anyone knows of another way to remove and install the seal without lifting the crank...

I believe here is where the O-ring goes. See parts fiche above.

DaveBarbier · « **Reply #361 on:** July 19, 2017, 04:43:51 AM »

I honestly don't see any damage in the seal. I'm probably missing something. I do see a little bit of black on the case, is that what you're talking about?

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AlekStooge · « **Reply #362 on:** July 19, 2017, 07:30:21 AM »

DaveBarbier · « **Reply #363 on:** July 20, 2017, 08:57:42 AM »

Can't tell the amount of damage but it seems minimal. Like just a scrape. I'd probably put some hondabond on it and seal it up.

Alternatively, I wonder if backing off the cam chain tensioner as far as it'll go will give you enough slack to gently raise the crank enough to squeeze in a new seal.

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AlekStooge · « **Reply #364 on:** July 20, 2017, 02:41:48 PM »

Haha great minds think alike. Already tried it, doesn't work. I had someone take a look at the seal and they said the same thing, Hondabond. Just waiting now on the little pins that sit in the basket part of the transmission. In retrospect I would've not opened it back up the O ring sits right behind a seal. Fiche shows it a little differently. Must be there for a reason though.

AlekStooge · « **Reply #365 on:** July 22, 2017, 08:21:36 AM »

I looked at my clutch while I'm waiting for parts. I think I might have asked this question before but didn't really resolve anything.

I measure my friction discs and they came out 2.7mm so manufacturing standard according to my Honda manual except Haynes says replace it if under 3mm. Going by the Honda manual. Don't know what that's about

The last friction disc so the one closest to you when facing, when the clutch is mounted measures 3.5mm. Looks like that is a different part number than the rest. Why is the last one thicker? https://www.cmsnl.com/honda-cb550k-1978-usa_model7222/partslist/E++08.html#results'

Also for the plates you are supposed to measure with a feeler gauge. What surface do you put the plate against to measure?

Thanks, I'm not going to replace the clutch plate/discs but I did get new springs already, Just some curiosities.

DaveBarbier · « **Reply #366 on:** July 22, 2017, 10:41:35 AM »

You can use a granite counter or thick glass. There is one friction disk that's fatter than the others. Not sure why, but that's the way it is. I don't think I found a spec for that one.

I ended up buy EBC friction disks for my 550 and I haven't had a problem. So maybe an alternative to OEM. Even if you don't replace them now, it's super easy to replace on the future. Lean the bike far to the left, unscrew the cover and work at it from there. If the gasket doesn't year then reuse it. That's what me and Rick did at the dyno and replaced springs in about 15 minutes.

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AlekStooge · « **Reply #367 on:** July 22, 2017, 02:37:43 PM »

Yeah pretty easy to replace on our bikes. With only 10K on it I'll just replace the springs. I don't get why the plates are measured with a feeler gauge instead of a caliper. I guess puting it on the granite is supposed to stimulate as if the plate was against the disc in the engine.

RAFster122s · « **Reply #368 on:** July 22, 2017, 02:40:26 PM »

Aftermarket discs will not measure the same as the OEM I read somewhere...
The steel plates should...

DaveBarbier · « **Reply #369 on:** July 22, 2017, 03:12:31 PM »

The actual clutch material will wear much more than the plate. The plate is checked for flatness. You don't want it warped. Glass is usually flat enough to test with as long as it's fairly thick. Thin glass can bend a tiny bit.

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AlekStooge · « **Reply #370 on:** July 22, 2017, 06:03:10 PM »

Ok I see.

DaveBarbier · « **Reply #371 on:** November 08, 2017, 05:14:07 AM »

Hey Alek, any update?

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skinsfn36 · « **Reply #372 on:** November 09, 2017, 08:31:46 AM »

This was a good read through.

I'll be going through something similar in the coming weeks.

Did you ever compile that list of rings and seals?

AlekStooge · « **Reply #373 on:** April 10, 2018, 03:11:23 PM »

I've been gone a long time. I haven't done anything to the bike over the past winter. I became a pilot so that became my focus.

I think I am just about ready to carry the engine to the garage, just a few more things to do.

I set valve lash to running clearance .004 intake and .005 exhaust (I believe it's correct I still doubt my self, I set it so there is little drag, I figure better a little loose than too tight).

I got the C5 set up. My problem was I didn't have a good ground through the backing plate. I thought the MAP wires ground the ignition. I just ran a ground wire from a bolt in the picture above. It lights up no problem now, always learn the hard way never easy.

Clutch is installed. I only replaced the springs as I mentioned in the post above. I had trouble torqueing it down and cracked a couple bolts around 60 inch lbs? Not sure why manual says 7.1 lbs to about 10 lbs. I ended getting 25mm length bolts with washers and just tightened it down snug.

I got the other right cover on and I wasn't going to put in the starter just make it a kick only. I was concerned oil might come through the opening, not sure that's true. I'm sure people take the starter out when racing to reduce weight so I think not.

Now, couple questions. With my new electronic ignition I read people scribe a new timing mark for TDC 1/4 should I do that? Please walk me through it. My degree wheel is still on.

How do I rotate the crank from now on? Alternator side? What about this old points nut?

I will be moving on to cleaning the carbs again, putting the oil pan/filter housing on, installing the intake manifold, moving the engine upstairs and laying electric out.

DaveBarbier · « **Reply #374 on:** May 22, 2018, 04:49:15 AM »

Hey Alek, get answers to any of hear questions? I just scrolled down in my feed farther down than normal and see you’re back at the rebuild.

Plug the starter hole if you’re removing the starter. You can buy plugs made for this purpose.

Unsure you still have the degree wheel on but if you do, set the engine to TDC 1/4 and then scribe a line on the case and on the alternator rotor. That’s your new TDC mark. I suppose there’s a risk of the rotor slipping and spinning on the crank end and making your marks off, but these rotors are pretty tight on there.

What’s your status on the motor now?

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Author Topic: 78 CB 550K motor rebuild (Read 60677 times)