Topic: CB550f - To crack the crankcase or not to crack the case

[Romhog]

Sort of a tongue twister subject but Here is by question first and then the backstory to why I'm even asking it.

1975 - CB550f - 26,000 miles on this well kept gem.
Do I have to crack open the crankcase to replace the countershaft oil seal ( 33x57x7 ) aka the one right behind the front sprocket? I've seen different answers to this and before I drill in to it and start pulling it out, I wanted to check.

Initially I went in with the gameplan of a full engine rebuild. (though I haven't had any transmission issues)
 I had the typical oil leaks on the left side, oil pump, gear shifter seal, etc. I was getting below 50 psi per cylinder, etc. Full valve job and gasket replacements. engine soda blast and repaint on the list as well.  The countershaft seal looks ok and not causing any leaking but that is easily falling under the "might as well" rule to replace.

Now, I have the engine on the bench at this point and most people would probably say why stop there! crack open the crankcase and be done with it!
But as I have checked the specs on my pistons/ springs, etc.  everything is still surprisingly in spec! So, I don't see any reason to tear in to the engine any further.  for fun I went ahead and replaced the gear shifter seal and that went well. Now I'm staring at the countershaft seal deciding if I should just drill in it and pull it out and replace it.

So again, is that possible on the 550f? I don't trust the shop manual as much in this area of the engine due to it being for the 550 , aka mine doesn't have the clutch lifter rod design, its the redesigned setup.  Also, even if the answer is yes, I can pull that seal, The other question is simply, shuold I crack open the crankcase if for anything to just replace the sealant holding it together? I feel its still factory sealed  and being that old I didn't know if that would be a good idea. Normally I don't bring this many thoughts in to a post, I just strait up ask the question but for this one I wanted to tell the whole story. So thanks for reading!

[bryanj]

Its over 40 yrs old and the 500/550 have no primary chain tensioner, having done a lot of these i would say you are so far in replace the primary(and cam)chain plus the cushion rubbers in the primary drive which will be as hard as rock now.
You can get a Kawasaki chain that is identical for the primary that costs less than half that of a Honda.

As to the seal if it dont leak leave it alone UNLESS you are splitting the cases

[Romhog]

So, if the advice is to replace those chains I guess I'm cracking the crankcase open to do that. The cam chain looks good, I'm shocked at 26000 miles that would be seen as a "replace it" item. but my tensioner and guide are both quite worn out so I guess that's a sign of some stretching.  I already have the guide and tensioner ordered for replacement.


Thanks for the advice as always Bry!
and thanks for the tip on the Kawasaki chain!

[bryanj]

I split a 10,000 mile 500 that had not been serviced right and owned by what I can only describe as a moronic animal and the primary + cam chains were like wet string, if the tensioner and cushion are worn the camchain will be BUT be advised that two grooves up the tensioner blade DOES NOT mean its worn out as the side plates of the chain wear into the rubber till the rollers touch. Put a straight edge (Steel Rule) across the rubber bit and see if the centre bit of rubber is a lot lower than the outer edges, if not and there is no cracking at the ends its good to use

[Little_Phil]

It's not a job to be afraid of. As far as I remember I only needed a modified 16mm bolt to pull the rotor and a slide hammer  (which I used a wheel axle off some other bike which I cant remember) to pull the primary shaft.
Primary had rubbed into cases a little and seemed to result in far smoother running.
Replaced the chain with Kawasaki 92057-1011 which was used on some more powerful bikes and primary rubbers (which are a bit pricey ().
Primary had rubbed into cases a little (32000 miles) and seemed to result in far smoother running.
But of course you need all the other seals and sealant and it does add up and you may end up looking at $250+
Just take your time and keep it clean.

[Romhog]

Thanks Phil and Bry!
On further investigation my primary drive chain has enough slop in it for me to replace that as well as the cam chain while I'm at it. The primary chain isn't touching the crankcase yet but maybe 1/2 from it.
Anyhow. I almost missed looking at those primary drive damper rubbers. I haven't cracked it open yet to look at them but these are the 8 individual wedged shape rubbers correct? I see some of them offered where they are pairs (so really only 4 parts)
Also. I'm having a hard time finding them to buy anywhere. Mostly just seeing them on google pics.
Any advice on a good place that sells them these days?

[RAFster122s]

8 small primary drive rubbers on 550

[bryanj]

You may have pics of the rear wheel ones, there are 8 small wedge shaped rubbers inside the hub where the primary chain goes over the outside and the starter gear is.
Here in UK i can order them from any Honda dealer part number 23114323000 they are same in all 500 and 550.

You have the engine out on the bench so you have done 90% of the work already.
2 hints

1 get the generator rotor off first whilst you have a big lump to hold
2 to remove primary shaft take bearing retainer off on the clutch side then after you take the oil pump off you can tap the end of the primary shaft with a soft drift to get shaft out, you dont need a slide hammer.

On rebuild VERY SMALL AMOUNTS of hondabond type jointing compound, oversize O rings at head gasket oil feeds, super cleanliness on rebuild and finally look up rubber band trick BEFORE attempting to fit rocker cover

[craz1]

Good info from everyone. I always replace the cam/ primary chains/seals and any other 40 year old rubber parts that may be in the trans when I take an engine apart. It an easy thing to do. I would also recommend using Locktite 518 when reassembling those cases. You don't have to rush when assembling those cases. I have done 6 cases so ar with excellent results.
https://www.henkel-adhesives.com/us/en/product/flexible-sealants/loctite_518.html

[Romhog]

thanks for the advice everyone. it really helps! look at what  I used to pull out the primary shaft. I was proud of my creativity on this one. I used the bottom bolt which had the same size threads along with the footpeg still attached as my "hammer" to pull it out.

[Romhog]

here are my bearings. I went to get a plasti gauge but my store didn't have them. I measured the cam shaft on no.1 and it's at 32.86mm which is in spec. won't know how much Clarence I have till I get the Plasti gauge but visually I think it's looking ok, what do you all think? oh and the 8 damper rubbers look good but are hard as a rock so I'll be replacing those, thanks again for pointing that out.
 

[bryanj]

As long as you know where they came from those shells are fine to reuse, showing small signs on not enough oil changes but not bad.
On assembly DO NOT oil the steel back of the shells OR the casing where they fit and if its going to stand for more than 7 days between assembly and running use an assembly lube, over here people tend to use graphogen but lots of others available

[craz1]

Yes those bushings look good but always a good idea to check with plastigage. Defiantly go out and buy some moly assembly lube.