Author Topic: 78 CB 550K motor rebuild (Read 60902 times)

Smudgemo · « **Reply #25 on:** August 07, 2016, 08:15:41 PM »

I'll be doing my '76 550 this winter, so thanks for the thread. Another few posts and I'll begin my project thread.
-Ryan

SOHC4 Cafe Racer Fan · « **Reply #26 on:** August 07, 2016, 11:24:17 PM »

Quote from: AlekStooge on August 07, 2016, 12:19:02 PM

So that's what everyone does order them one by one? I'll look Elan up.

He's on Facebook too.

AlekStooge · « **Reply #27 on:** August 11, 2016, 11:35:30 PM »

Ordered oil seals, pucks and O-rings after making a list of OEM part numbers. I will post the list once I know 100% it's correct, so others don't have to go through the cross referencing and hunting I had to because a set doesn't exist. I also ordered a primary chain and the cam chain was not available at the moment.

I've been studying DaveBarbier's thread. I'm at the point of plastigaging my crank bearings. I've never used plastigauge before so I watched a couple of videos on it. It seems I don't need to do anything with the connecting rods and I don't want to because of the stretch bolts. Is there any other bearing I should plastigauge while I'm at it?

I didn't order bearings but I should be good since I got the engine with under 10K on it.

NobleHops · « **Reply #28 on:** August 12, 2016, 03:22:56 AM »

Another thing to inspect at this moment is the engagement dogs on the transmission gears. You'll see them if you take each shaft and separate the pairs of gears that engage with each other along the shaft - one will have male "dogs" and the other will have slots that the dogs engage with. A little wear and rounding is to be expected, but if you see gouges or really rounded over shoulders then it may be wise to seek a replacement.

The other item to inspect closely is the shift forks - I think there is a spec for width at the tip, but if there is big wear or they are bent it will be obvious. Also look for scorching or unusual wear. At 10K miles I would not expect to find trouble with either of these unless the engine had a low oil episode or was abused, but as with everything else you are lovingly fixing in this engine, this should be looked at now, you know, WHILE YOU'RE THERE. :-)

N.

AlekStooge · « **Reply #29 on:** August 12, 2016, 05:50:09 AM »

Quote from: NobleHops on August 12, 2016, 03:22:56 AM

Another thing to inspect at this moment is the engagement dogs on the transmission gears. You'll see them if you take each shaft and separate the pairs of gears that engage with each other along the shaft - one will have male "dogs" and the other will have slots that the dogs engage with. A little wear and rounding is to be expected, but if you see gouges or really rounded over shoulders then it may be wise to seek a replacement.

The other item to inspect closely is the shift forks - I think there is a spec for width at the tip, but if there is big wear or they are bent it will be obvious. Also look for scorching or unusual wear. At 10K miles I would not expect to find trouble with either of these unless the engine had a low oil episode or was abused, but as with everything else you are lovingly fixing in this engine, this should be looked at now, you know, WHILE YOU'RE THERE. :-)

N.

That brings me to my next question. What are false neutrals? The reason I ask is because when I rode the bike I remember shifting down into neutral one time and I got a grinding noise and obviously not neutral. I guess it could have been operator error as well but it sounds like false neutral would be an accurate way to describe this. How do I check this?

calj737 · « **Reply #30 on:** August 12, 2016, 06:36:22 AM »

"fasle neutral" is more accurately when you shift to a gear, but find "neutral engagement" between gears, making you feel as though you've hit neutral, not 3rd, 4th or 5th. But "grinding" when shifting down to neutral surely needs investigation.

flatlander · « **Reply #31 on:** August 12, 2016, 06:43:51 AM »

cool, i'll follow along... sounds like you're doing pretty much the same setup as i did.

AlekStooge · « **Reply #32 on:** August 12, 2016, 08:55:43 PM »

Quote from: calj737 on August 12, 2016, 06:36:22 AM

"fasle neutral" is more accurately when you shift to a gear, but find "neutral engagement" between gears, making you feel as though you've hit neutral, not 3rd, 4th or 5th. But "grinding" when shifting down to neutral surely needs investigation.

I don't see much wear on my transmission components, so I wouldn't know what to look for. I think I just over shifted into first and got that noise. I've had it happen on my other bike so it's probably just me.

Anyways I don't think I'll have to do anything with the connecting rods but I'd like to get that confirmed?

Quote from: flatlander on August 12, 2016, 06:43:51 AM

cool, i'll follow along... sounds like you're doing pretty much the same setup as i did.

Welcome

AlekStooge · « **Reply #33 on:** August 24, 2016, 06:38:00 PM »

Here is a picture of one of the dogs. I'd say these look pretty good and don't need to be replaced.

I received most of my seals, puck and O-rings except a few on back order from DavidSilver along with the cam chain and primary chain.

Do I plastigauge with new seals in or use the old ones? What about the connecting rods?

lightsareout · « **Reply #34 on:** August 25, 2016, 05:01:41 AM »

Following along; I plan to do a simlar build with one of the 550 motors I have

Darren Jakal · « **Reply #35 on:** August 25, 2016, 05:30:17 PM »

Just picked up a 78 550 so I'll be watching this.

Thanks, Darren

AlekStooge · « **Reply #36 on:** August 30, 2016, 09:03:18 PM »

I got all my seals and O-rings as well as the primary chain and cam chain. I'm going to plastigauge my crank bearings tomorrow. Does installing the gasket between the cases making a difference? Also the seals?

If the clearance checks out good, which I'm confident it will. Then I'll start working on closing the cases back up. For the gasket surfaces I will use Hondabond, but where should I use oil vs. assembly lube? What about wheel bearing grease for O-rings?

Can anyone comment on the dogs?

calj737 · « **Reply #37 on:** August 31, 2016, 05:07:24 AM »

Head gaskets don't effect plastigauge of the crank.

Use Assembly Lube on all hard parts- cam lobes, crank journals, etc. Use oil on O-rings as they hold oil back. Use wheel bear gin grease on bearings. Basically use the lubricant that each part lives in when assembling.

Your dogs look fine in that picture.

AlekStooge · « **Reply #38 on:** August 31, 2016, 08:51:14 AM »

For some reason I thought there was a gasket between the cases.

calj737 · « **Reply #39 on:** August 31, 2016, 09:52:24 AM »

There is, but it doesn't effect the crank to case half spacing.

AlekStooge · « **Reply #40 on:** August 31, 2016, 10:31:29 AM »

Unless you are referring to the base cylinder gasket then I don't see it,

AlekStooge · « **Reply #41 on:** August 31, 2016, 12:49:11 PM »

Is there a torque spec for the crankcases? I going to be using an Allen head set for my engine? I guess I'll have to get more bits and an adapter for my torque wrench if there is.

calj737 · « **Reply #42 on:** August 31, 2016, 01:57:04 PM »

The Allen heads are for the covers only, and there's not really a need to torque them (they replace 6mm bolts and their torque spec is about 6-7 Ft/Lbs). The crankcase torque value is in the manual, but again, its pretty low so go easy.

AlekStooge · « **Reply #43 on:** August 31, 2016, 02:16:58 PM »

I looked in Clymers which one are you referring to?

Yeah I just realized the allen heads are for the covers and not the cases.

DaveBarbier · « **Reply #44 on:** September 01, 2016, 02:13:22 PM »

Just to clarify a bit. When plastigaging don't use any lube on the crank. It goes in dry, as dry and clean as you can get it.

Don't put any sealant on the case halves yet, wait until you're buttoning it up completely.

AlekStooge · « **Reply #45 on:** September 08, 2016, 07:10:50 AM »

Looks like I'll be getting new bearings. I got a reading of .0015 across the board. What's weird is that the plastigage crushed not in the center but on the sides. Is that normal?

Getting new engine hardware as well.

AlekStooge · « **Reply #46 on:** September 08, 2016, 07:35:04 AM »

I'm looking at ordering new bearings. I've been told the code for the letters and colors is stamped on the back of the cases. All I see what look like 5 Bs or couple of them Rs. I don't understand the manual either. CMSNL looks like it is missing one bearing on it's list http://www.cmsnl.com/honda-cb550k-1978-usa_model7222/partslist/E++13.html#results

Please help

DaveBarbier · « **Reply #47 on:** September 08, 2016, 08:16:47 AM »

You don't need new bearings. The manual says if the clearance is GREATER than .003" they should be replaced. A tighter tolerance means the plastigage will squish MORE. If you're truly measuring .0015" then you're well within spec. The plastigage won't squish at all in the middle because the bearing has an oil channel. Kind of hard to see in your picture but if what you're seeing is similar to mine (look at this link from my build thread http://forums.sohc4.net/index.php/topic,140833.msg1601137.html#msg1601137) then you're good to go!

AlekStooge · « **Reply #48 on:** September 08, 2016, 09:17:16 PM »

Dave is right ^

I was mistaking the values of numerals being reversed as if they were negatives. Forgot we haven't made it past zero yet. That with also seeing the largest mark on the plastigage with .001 think thinking it was the greatest.

My mistake

DaveBarbier · « **Reply #49 on:** September 09, 2016, 04:14:14 AM »

And I f'ed around during math class. Just think what I'd know if I listened!

News:

Author Topic: 78 CB 550K motor rebuild (Read 60902 times)