Topic: CB550K Bottom End Rebuild: Questions, Opinions, Advice, Information, Etc.

[Darren Jakal]

CB550K Bottom End Rebuild: Questions, Opinions, Advice, Information, Etc.

Hi All, I hope everyone had a great Solstice (Winter for the North and Summer for the South)!

I have a potential runner 1978 CB550K that is almost done (I just need to purchase shocks, mirrors and finish a few details) and a 1977 CB550K roller frame and engine minus the head and all parts above.

I bought the roller to get a few needed parts for the runner (rear wheel mainly), but I decided to get into the engine as a Covid Project. First thing I noticed was that the PO was somewhat ham fisted and there are a number of marred mating surfaces and blue sealant on the case halves.

Because of the case damage I had an eye out for replacement ones and found them at a local used motorcycle shop for $60.00 CDN. Great price so I picked them up hoping to simply move the internals over.

Well you know how that goes. The roller engine has main bearings and con rod bearings that are so new you can clearly see the shell colour still on the side (three green and two brown mains and four green con rod). The new cases I picked up also have almost new looking main bearing shells and I think I can find what I need from these once I Plastigauge them.

My questions will all be about other engine parts and what others are doing to either determine that they are still good or need to replace. Then the question is what did you replace with and where did you find them.

So to start I will ask about Primary Chains. The one in the roller is not new but doesn’t seem to be completely worn out either. I have found some on ebay and they are back ordered on David Silver Spares, but has anyone ever heard of these guys below:

Part#: 23131-426-003 Primary Chain

https://www.giatlahuep.com/index.php?main_page=product_info&products_id=745865

They claim to sell a made in Japan chain for $73.00 CDN and free delivery that seems too good to be true. David Silver wants about $121.00 CDN for an aftermarket plus $25.00 US delivery. Anyone know if either of these chains are OK? I have read that Honda still makes these but I have not found a Honda dealer with one.

http://forums.sohc4.net/index.php/topic,137101.0.html

How about Primary Shaft Bearings? I have done a bunch of reading from this site and the views are mixed. There is one in the new cases and the ones on the roller. They appear to be in good working order. Opinions or insights?

Next would be Primary Drive Cush Rubbers. Not that expensive, but the ones I have look great, however they are dam hard. Never having felt what a new one is like I have no idea how soft they actually are. Any comments welcome.

http://forums.sohc4.net/index.php/topic,156547.0.html

Part#: 23114-323-000 Cush Drive Rubber

Next would be Cam Chain Tensioner Blade. The one I have from the roller is cracked but not that worn. David Silver has an aftermarket one for $47.37 CDN. Anyone tried this one out?

I will leave it at that for now. I know I will need a new Cam Chain as well as a Cam Chain Guide as the roller was missing these parts. Again David Silver has these as does places like 4into1. Anybody have others options they know about?

Thanks Everyone, Darren

[bryanj]

Definately new primary and cam chain as primaries wear into the casings when worn and there is no visual check for wear. There is a Kawasaki chain that is identical and cheaper but maybe not as cheap as the one you found, i located it using cmsnl.
Definately new cush rubbers in primary drive or the chain will wear quickly, the "hard" is the problem.
If the cracks on cam chain tensione look like they go all the way through and bits could come off replace it.
Clean thoughroughly all the blue crap off and make sure all oilways are supper clean.
Slightly oversize O rings for head gasket are a good idea(search Hondaman) and dont forget the soft alloy washers between the steel end brackets and cam cover

[Darren Jakal]

Thanks Bryan !

Great info. The old roller engine has the blue sealant and the newer cases I bought have what looks to be original sealant. The roller engine had plugged oil restrictors and why I believe the bike was junked and the head gone.

I will clean everything super well on the new cases and I have already inspected and cleaned out the oil passages in the roller crankshaft (it was surprisingly spotless).

The cracks on the tensioner do not go all the way through, but I may replace it with the David Silver aftermarket one. Just wondering if anyone had any experience with it as I have heard horror stories about aftermarket products for the sohc/4s.

Again great advice on the o-rings and washers. I’ll put them on my list.

Cheers, dj

[bryanj]

No problem, i would advise geting a proper Honda manual and repeatedly reading the bit about fitting the cam cover and care not to bend valves.
There is no specific 550 manual, you start with the 500 and go through supplements on the 550's

[Darren Jakal]

Thanks Bryan, I’ve been using the manual found here as it is a good as I have seen.

Yes, the 78 differs from the original cb500, but you are right the supplements make up for that I have found.

Lots of good information and advice here as well. I’ll continue this thread with more information on parts and suppliers as I find it.

Cheers, dj

Just looking at the cmsnl site. You Europeans are lucky. Convert from CDN to  Euros and shipping makes this a bit expensive.

[HondaMan]

If you can tolerate shipping from New York (USA) there is an eBay seller JTMarks who has lots of OEM Honda parts. I just did 2 550s and a 400F that needed primary chains: he had new NOS parts. Had to dissolve the old grease (2 days sitting in xylene) toe get them flexible again, then cleaned and soaked in 30w oil overnight before installing them. Perfect fits, all.

[Darren Jakal]

Hey thanks Hondaman. What a treasure trove of Honda parts!

https://www.ebay.com/itm/Honda-New-350-Primary-Chain-400-500-550-650-CB350F-CB400F-CB500K-23131-426-003/332275772003?epid=1223066411&hash=item4d5d2dea63:g:JJYAAOSwDk5T94in

Found the primary chain. Seems like a reasonable price for OEM Honda. Unfortunately it states right on the page that he doesn’t ship to Canada. Dam.

Cheers, dj

[754]

Could ask him , you never know.

[Little_Phil]

Part#: 23131-426-003 Primary Chain

https://www.giatlahuep.com/index.php?main_page=product_info&products_id=745865
That chain is similarly marked like the one from DSS and a good price.

For genuine I've used a couple of the genuine Kawasaki chains 92057-1011. It was originally on their 400/4 and also used on the 550 zephyr. Prices vary wildly, but can be picked up cheap.

[drumstyx]

I can't speak to the 550 specifically, but regarding the roller bearings in the case: I replaced all the (roller) bearings in the bottom end of my CB750K8, and even had grooves ground into the 2 bearings with positioning grooves at a local grinding machine shop, and it only cost something like $250 including $50 for getting those grooves cut. That was EVERY ball bearing in the engine. The needle bearings (for the kickstart gear, if I recall correctly?) were another $20 or $30 on ebay, but probably didn't need replacing -- just were required for me because it's difficult to get them out without damage and I had the cases vapour blasted.

That is to say, IMO, if you're down there anyway, replace the bearings. I've never heard of failure or wear of those bearings, but they're technically "wear" components, as all bearings are, so why not.

[Darren Jakal]

Hey thanks everyone for the replies.

I will take all suggestions into account and make a summary of what I do here.

This being a unnecessary Covid project I am trying to keep costs down (at least until I finish the rider). Thing is this engine seems to be in very good condition and I have no idea why the PO decided to split the cases. If it wasn’t for the blue case sealer I would have just bored the cylinders and found the top end parts.

It is evident that the PO replaced all the crank and con rod bearing shells (I can still see the colour designation of them), but every thing else seems pretty pristine. I have mic’ed the crank and it is in perfect condition. I will continue to hunt down the parts and even if I don’t purchase them I will post my finding here so others may benefit from the search.

Cheer, Darren

[bryanj]

550 gearbox bearings are very robust and unless corrosion damaged should be fine.
Oil pump cover O ring(not in parts book seperate) is worth changing but you need an impact driver with jis bits to undo the 3 screws. Its a 46x2 O ring and a GL 1000 part fits, the number is listed on here somewhere.

[Darren Jakal]

Good to know about the robust bearings, Bryan. They all look in great shape and I have to say the cost of all of them was getting up there.

I have JIS drivers and have dismantled and reassembled the oil pump (this is my MO, I disassemble things and then right away reassemble them to get to know how things go together. I then leave them as sub-assemblies until they are ready to be overhauled and placed into the case). I’m planning to find all the seals for the oil pump and will post my findings here. Thanks for the heads up on the 46x2 o-ring.

Cheers, dj

91305-326-003 46x2 Oring for the cover

partzilla:

https://www.partzilla.com/product/honda/91305-426-003

[bryanj]

There is a UK member, nurse julie, who does O ring kits for the oil pump and carb O ring kits for the 500/550 up to 76

[Darren Jakal]

Great Bryan, this is a 77 model. Is there much difference that you know of (oil pump, I know the carbs are very different PD and all that).

Thanks, dj

[bryanj]

77 should have the modified cam cover with pinned rocker shafts that cant rotate, there were a few "in use" differences to parts and the god awful.PD carbs, plus bodywork changes.

[Darren Jakal]

I have been on the lookout for the 77 or 78 head, but now I’ll spend money on the bottom end stuff and worry about that later.

If things go a certain way I can see myself redoing the top end in the 78 Runner after I run it next summer. I expect it to be leaking going by what I saw when I got it.

So if I have a built-by-me lower end I would think about swapping the head from the 78 and running that. Of course once I have the head off I might want to do additional work. As if it will ever end, ha.

Later, dj

[bryanj]

Any 500 or 550 head is the same, its only the cam cover thats modified and the early ones will run quite happily as long as the rocker shaft holes are not ovaled

[Darren Jakal]

That’s right Bryan, I forgot. Makes looking for a head easier with all years available. The cover is what I want in the 77, 78.

Cheers, dj