1975 CB500T Exhaust Camshaft wear & oil leak

[JAY-CB500T]

I have traced an excessive oil leak coming from the points cover. Oil is coming out of the seal behind the advancer.
While doing this inspection ive found a lot of up & down play in the end of the Exhaust Camshaft, the aluminium housing has worn so I replaced the housing with a better condition secondhand one and a new seal. All seemed OK until I went on a ride and come back to oil leaking out of the points cover again. So I think I need to replace the exhaust camshaft, it's quite difficult to measure while it's in the engine. But my question is, what has caused this excessive wear? I have rebuilt the engine and replaced all seals, gaskets, rings, professionally done honed barrels and lapped valves. The bike runs sweet as a nut in my opinion apart from this oil leak. I've followed videos for the rebuild, settting valve timings etc and fitted electronic ignition which all works great. I really don't want to put new parts on for the same issue to happen again.

 

[ancientdad]

Without seeing the inside of the engine it's hard to be sure, but I can assume you have an oil flow issue on the left exhaust cam bearing. I've been there myself on a DOHC 450 and it can be maddening. Since you did the rebuild prior to joining, it will take many questions and lots of pictures to figure it out once you pull the engine and tear it down. I know that's not what you want to hear, but the process of finding the reason for the lack of oil flow to the left exhaust that led to your ruining 2 cam bearings will have to be found, and just replacing the exhaust cam in the frame - which CAN be done if all proper safeguards are followed, I've done it many times - won't be enough because if the oil flow problem is not identified you'll be right back here again in short order.

 

[JAY-CB500T]

Thanks for the quick reply. So, your right there's a lot I did wrong in the re-build like not taking proper measurements of the cams when putting it back together.
I had the top end, block, pistons and valves all professionally checked for tolerances by a local performance engine building company near me. So I am confident those parts are ok. The cams and followers in my non-professional opinion "looked ok".
I've since read in a previous thread on here about not leaving the bike to warm up on the kickstand as the oil could not be getting to the pump which makes perfect sense. Also, I have been guilty of not leaving the bike a full 2 minutes to warm up before riding it.

I did find when I had the leak to start with that my oil was low, didn't think id need to check the level that often as I've hardly rode it since the re-build. So, with that I decided to change the oil around the same time as fitting the new seal and journal for the left exhaust camshaft.

I rode the bike twice totalling 2 hours tops and that's when I started to see the oil coming out of the points cover again.

So, I can make the assumption its getting oil otherwise it wouldn't be coming out of the cover. But how long it took to get there and if the cam was worn before installing I'll never know.

I've got some eBay journals and a new second-hand cam on the way, so hopefully I can take some more pre-cautions regarding the warm up time and kickstand issue. Fingers crossed that's all it was. Will feedback the state of the old parts when I get them out.

 

[JAY-CB500T]

Without seeing the inside of the engine it's hard to be sure, but I can assume you have an oil flow issue on the left exhaust cam bearing. I've been there myself on a DOHC 450 and it can be maddening. Since you did the rebuild prior to joining, it will take many questions and lots of pictures to figure it out once you pull the engine and tear it down. I know that's not what you want to hear, but the process of finding the reason for the lack of oil flow to the left exhaust that led to your ruining 2 cam bearings will have to be found, and just replacing the exhaust cam in the frame - which CAN be done if all proper safeguards are followed, I've done it many times - won't be enough because if the oil flow problem is not identified you'll be right back here again in short order.

I'd be interested on how you can change this camshaft while in the frame? Not sure what the proper or un-proper safeguards are? Might save me some time.

 

[ancientdad]

I'd be interested on how you can change this camshaft while in the frame? Not sure what the proper or un-proper safeguards are? Might save me some time.

But if you do that, you will never be sure of any possible oil flow issue. Not to be critical of your engine assembly work, but many do not realize how critical certain things are to avoid when assembling a Honda engine from that era including gasket surface cleanliness, oil gallery cleanliness and proper gasket adhesive to use ( or where to use it, if at all). BUT, there's a question I have to ask at this point because I went through it and it took me a few tries of going through the entire oiling system before I found the simple error I made that caused it all. I'll show you pictures because the explanation in words is more complex, but the centrifugal oil filter valve in the small cover on the right crankcase cover can be reassembled incorrectly if you somehow took it apart for cleaning, which I did for the first time ever in my life of working on Honda engines when I built the engine for my red 450. The entire bottom end of my engine was pretty gunked up with sludge so I wanted to clean everywhere, and this little slip I made caused the oil filter valve to intermittently block the flow to the top end. It DID get some oil but not consistently, which resulted in me replacing 3 cam bearings and having my exhaust camshaft (a high performance cam at that) needing the left exhaust lobe refurbished as well as replacing that follower. First, the damage:



Now, the cause:





Note the 2 red arrows pointing to the small 'holes' in the casting of the small cover in the second pic, and the 2 tangs on the valve in the first pic - the tangs have to be located in those 'holes' in the cover or the valve moves around and intermittently blocks flow out of the oil filter and to the top end.

 

[ancientdad]

It all started at this point in my build thread.

CL450 project reboot, street-legal this time

This attempts to be a synopsis of the nearly 500 posts of my "little red monster" build from another forum long ago... When I was 19, I built a CL450K5 into a modified class drag bike Ever since letting it go for one month's rent on a one bedroom apartment ($125) while broke and out of...

www.vintagehondatwins.com

 

[JAY-CB500T]

But if you do that, you will never be sure of any possible oil flow issue. Not to be critical of your engine assembly work, but many do not realize how critical certain things are to avoid when assembling a Honda engine from that era including gasket surface cleanliness, oil gallery cleanliness and proper gasket adhesive to use ( or where to use it, if at all). BUT, there's a question I have to ask at this point because I went through it and it took me a few tries of going through the entire oiling system before I found the simple error I made that caused it all. I'll show you pictures because the explanation in words is more complex, but the centrifugal oil filter valve in the small cover on the right crankcase cover can be reassembled incorrectly if you somehow took it apart for cleaning, which I did for the first time ever in my life of working on Honda engines when I built the engine for my red 450. The entire bottom end of my engine was pretty gunked up with sludge so I wanted to clean everywhere, and this little slip I made caused the oil filter valve to intermittently block the flow to the top end. It DID get some oil but not consistently, which resulted in me replacing 3 cam bearings and having my exhaust camshaft (a high performance cam at that) needing the left exhaust lobe refurbished as well as replacing that follower. First, the damage:

View attachment 25824

Now, the cause:

View attachment 25825

View attachment 25826

Note the 2 red arrows pointing to the small 'holes' in the casting of the small cover in the second pic, and the 2 tangs on the valve in the first pic - the tangs have to be located in those 'holes' in the cover or the valve moves around and intermittently blocks flow out of the oil filter and to the top end.

Interesting, I'll have to check this out over the weekend. Thanks

 

[ancientdad]

Interesting, I'll have to check this out over the weekend. Thanks

The question is, did you take that cover apart to clean it? When I worked at Honda shops as a young man they were too new to ever need it, but when I bought my CL450K5 in late 2016 they had obviously been around decades longer and I figured it would be smart to do. I just didn't pay close enough attention to the correct assembly when I took it apart, which resulted in me chasing my tail and spending money for a while until I discovered what I'd done wrong.

 

[JAY-CB500T]

The question is, did you take that cover apart to clean it? When I worked at Honda shops as a young man they were too new to ever need it, but when I bought my CL450K5 in late 2016 they had obviously been around decades longer and I figured it would be smart to do. I just didn't pay close enough attention to the correct assembly when I took it apart, which resulted in me chasing my tail and spending money for a while until I discovered what I'd done wrong.

I'm fairly confident i would of cleaned it during the rebuild, spraying carb cleaner into every hole or poking mini bottle brush into the holes. I remember the outer cover needing to be lined up correctly but not much about the orientation of parts. I printed off the exploded drawings to make sure I wasn't missing any part's as well.

 

[JAY-CB500T]

Other than releasing the copper washer on the top of head on the right side to allow oil out, how else can you check the cams and followers are getting the correct flow of oil?

 

[ancientdad]

Other than releasing the copper washer on the top of head on the right side to allow oil out, how else can you check the cams and followers are getting the correct flow of oil?

I hate untorquing something to check oil flow, because unless you keep the torque wrench handy then you've lost the torque value on that stud after going over them carefully and making sure they're all equal. What I've done in the past is leave the exhaust valve cover off, lay a couple of towels over the exhaust pipes and start the engine to watch for oil flow at both ends of the cam and out of the orifices in the lobes flowing over the followers. But no matter which way you do it, you can't be certain of the quantity of oil getting there and if it's being restricted in some way.

 

[jensen]

Did you, or a company bead blasted, or vacuum blasted your crankcases ?

 

[ancientdad]

Did you, or a company bead blasted, or vacuum blasted your crankcases ?

Good point, if not completely cleaned up there could have been blast media stuck in places that came loose after heat and oil circulation.

 

[JAY-CB500T]

Interesting, I'll have to check this out over the

Did you, or a company bead blasted, or vacuum blasted your crankcases ?

I had a professional vapour blasting company do the vapour blasting before they did the ceramic coating.

 

[ancientdad]

I had a professional vapour blasting company do the vapour blasting before they did the ceramic coating.

The crankcases were ceramic coated? Interesting, I've never had anything done to crankcases except having touch-up painting them myself. I wonder if any passages were restricted or clogged during the process.

 

[JAY-CB500T]

So, I haved checked out the oil filter cap and all was lined up in the correct hole's as it should be. I did remove the filter to find some silvery gunk in there which seemed almost rubbery, maybe old grease?

 

[JAY-CB500T]

And it's clear the camshaft and journals are completely trashed. But the sad thing is, I couldn't see any blocked oil ways or holes, spraying brake cleaner in them and coming out the other ends OK. The right side actually looks alot worse and that's the end where the oil is ment to come up. However, oil did come out of the cover when I removed it and I believe oil had been getting to the followers. Just can't understand how it's not got to the journal's? Maybe i didn't let it warm up to many time's and it just got worse and worse by keep riding it?

 

[ancientdad]

That wasn't caused by short or poor warmup. You have a partially blocked passage somewhere, has to be to cause that much damage. If this was mine I'd be pulling the engine today, there's no way to be completely sure of anything at this point without inspecting everything. When mine had the intermittent oiling problems, it was getting oil to all the cam bearings and followers but the interruptions caused by the oil filter valve were just enough to slightly starve the one furthest from the pump - the left exhaust. Since your tach side is also badly damaged, I'd guess there's some blockage somewhere in either the forward right side stud passage or in the right cam bearing where the tach drive is. What about the tach drive itself and the tube that extends into the right end of the camshaft?

 

[jensen]

If it was due to oil starving, I would expect to see blueish, golden area's on the cam journals. Also, the very "nice" straight grooves pointing to debris, blasting media residue or something else. I also never saw that stuff that's coming out your filter, could that be debris mixed with oil?

Like AD says, take it apart completely to avoid issue's in the future. I would try to find out what that "gunk"is, by solvng it in petrol and filter with a coffee filter. How did the filter element look like ? If this gunk went trough your filter, it probably found also the way into your crank.

Once I saw a cam with these kind of heavy damages, the engine was full of glass particles, and I mean, not the glass particles used by bead blasting, but solid particles of glass.

 

[ancientdad]

I also never saw that stuff that's coming out your filter, could that be debris mixed with oil?

I agree about the debris in the filter, it's hard to tell what it's made of looking at that picture but it certainly seems to have a lot of metal in it.

 

[jensen]

Ceramic coating generally refers to a coating that chemically consists of SiC or silicon carbide. To begin with, this substance is much harder than SiO2 (glass coating). So hard in fact that it is used as a synthetic diamond in industrial applications. Could it be possible that this coating, or particles from this coating, found it's way, somehow, into the oil ?

 

[ancientdad]

Ceramic coating generally refers to a coating that chemically consists of SiC or silicon carbide. To begin with, this substance is much harder than SiO2 (glass coating). So hard in fact that it is used as a synthetic diamond in industrial applications. Could it be possible that this coating, or particles from this coating, found it's way, somehow, into the oil ?

That sounds like a strong possibility.

 

[JAY-CB500T]

That sounds like a strong possibility.

The cersmic coating is superthin and all of the internal areas were masked off. The thought did cross my mind regarding the vapour blast media during the rebuild so I made sure I put brushes down oil holes and blew cleaner down all the holes. Every part was thoroughly cleaned before putting back together.
There is no filter material in the oil filter, the gunk did seem to have metal dust within it, and the first oil change did have that metallic shimmer to it.
Unfortunately the battery on my vernier is dead atm so I can not finish the measurements of the top end parts to know exactly what needs replacing.

 

[JAY-CB500T]

Also, I'm pretty sure the ceramic coating is used on pistons and internal parts anyway due to the thermal properties in it.

 

[ancientdad]

The cersmic coating is superthin and all of the internal areas were masked off. The thought did cross my mind regarding the vapour blast media during the rebuild so I made sure I put brushes down oil holes and blew cleaner down all the holes. Every part was thoroughly cleaned before putting back together.
There is no filter material in the oil filter, the gunk did seem to have metal dust within it, and the first oil change did have that metallic shimmer to it.
Unfortunately the battery on my vernier is dead atm so I can not finish the measurements of the top end parts to know exactly what needs replacing.

The oil filter is a centrifugal one so you won't find any 'filter material' in it. If you already pulled the engine, we could be a lot more help if you post pictures of all the parts so we can see them too. When these engines were built there was no ceramic coating used. What Jensen meant is if some tiny pieces came free and maybe got crumbled up in the primary drive, ended up in the oil flow and somehow got past the centrifugal filter to the top end. Anything hard would get in the cam bearings and rough up the aluminum easily, or possibly clog the passages if enough of it so it helped starve the exhaust cam of oil to the bearing covers.

 

[JAY-CB500T]

Possibly a question for a new thread but do you know of anyone who's done the Cappellini needle bearing upgrades to the camshaft bearings?

 

[ancientdad]

No need for a new thread, we've had a couple members who have come and not stayed long who had spent the money on it. The issue, as I recall, is that you have to do away with internal oiling and use their external oil lines and their paper filter setup but I may be remembering wrong.

My 450 engine is proof that when the oiling works as designed, even with the stock oil pump, the engine survives very well given proper warmup. Did you look at my build thread and this video? You don't need to spend that money.

 

[JAY-CB500T]

The oil filter is a centrifugal one so you won't find any 'filter material' in it. If you already pulled the engine, we could be a lot more help if you post pictures of all the parts so we can see them too. When these engines were built there was no ceramic coating used. What Jensen meant is if some tiny pieces came free and maybe got crumbled up in the primary drive, ended up in the oil flow and somehow got past the centrifugal filter to the top end. Anything hard would get in the cam bearings and rough up the aluminum easily, or possibly clog the passages if enough of it so it helped starve the exhaust cam of oil to the bearing covers.

Arh I see what you mean now, potential debris getting past the filter and getting stuck in the cam. The engine currently remains in frame with the tank, carbs and camshafts removed. The followers removed aswell as there's weren't checked for tolerance when I re-built it either.
I tempted to stick new cams back in before a full strip and clean and run it to see the oil come out like you said with the covers off.
In the long run I think I'm going to look more into upgrading this system as it seems the 450's/500's commonly get starved of oil

 

[ancientdad]

In the long run I think I'm going to look more into upgrading this system as it seems the 450's/500's commonly get starved of oil

Do as you will, but I'm telling you if the engine is built right you will not have these problems if you treat it properly. I'm here to offer my experience and reassurance about it based on my drag racing experience with a DOHC 450, thrashed for almost 3 years and probably 1000 or more runs, as well as my street bike now, all on the stock oil pump and oiling system. It just needs to be rebuilt right, and you'll never know enough about what happened if you don't pull the engine and tear down the top end the right way.

 

[JAY-CB500T]

I know what you mean and your right, it's the proper thing to do. But what more am I going to to see taking the top end off? Or do you mean splitting the crankcase again aswell?

 

[ancientdad]

If you don't want to pull the engine - and if you're going to do both cams in the frame, it is more difficult and a little tricky - then at least pull the right crankcase cover off, pull the clutch and oil pump and inspect the pump and blow out the passages to the top ed through the gallery opening at the base of the cylinder studs. But if you see any noticeable debris coming out of the feeds into the head in the openings for the cams, it will need to be flushed out completely and that may not be fully accomplished without disassembly. You'll want to do everything that can be done to check the oil supply from the pump through the centrifugal filter through the cover and up the studs and other than full disassembly, the best way is there. And the feed to the transmission shafts too.

 

[LongDistanceRider]

Some questions about this ceramic coating for you.
What is the product name? Company that applied it?
Applied only to exterior surfaces or interior as well?
Why a ceramic coating?
You are correct that a ceramic coating is applied to piston tops/domes, valve faces and combustion chambers to contain the combustion chamber heat after ignition. Heat = energy = power. It's also used to coat exhaust manifolds, turbochargers, etc. to keep the exhaust gasses hot and flowing fast. I have 2 engines with TBC coating on the pistons done by SwainTech https://swaintech.com/race-coatings/motorcycle-coatings/
I wouldn't consider using any ceramic coating in any other places as it holds heat in rather than dispersing it, especially on an air/oil cooled engine.

 

[JAY-CB500T]

Some questions about this ceramic coating for you.
What is the product name? Company that applied it?
Applied only to exterior surfaces or interior as well?
Why a ceramic coating?
You are correct that a ceramic coating is applied to piston tops/domes, valve faces and combustion chambers to contain the combustion chamber heat after ignition. Heat = energy = power. It's also used to coat exhaust manifolds, turbochargers, etc. to keep the exhaust gasses hot and flowing fast. I have 2 engines with TBC coating on the pistons done by SwainTech https://swaintech.com/race-coatings/motorcycle-coatings/
I wouldn't consider using any ceramic coating in any other places as it holds heat in rather than dispersing it, especially on an air/oil cooled engine.

It's only applied to the external parts. Mainly because it's better hard wearing compared to paint, it doesn't discolour or chip off, easy to clean. My understanding is they have different formulas for different applications. Please checkout the their website for full information. https://chameleonvapourblasting.co.uk/

 

[jensen]

If the ceramic coating is applied well, it won't lead to this issue, so, if you say it's highly unlikely that the company did a bad job, so it is. And since you trust this company and you cleaned the oil passages thoroughly, you take that of the list too.

Looking at the cam shaft bearing area, I'm still thinking that hard particles fit the damage, either beat particles, or hardened metal parts (bearing parts, gear parts etc). You're sure that beat particles are not the reason, the damage is due to hardened steel particles, either from other parts then the camshafts, or the camshafts themselves.

One other thing to mention, from what I can see in your pictures, the cam lobe, close to the bearing surface, looks very clean, and "unharmed". I have seen many damaged camshafts, and when the bearing is damaged due to oil starvation, the cam lobes will go first, because before the oil reaches the bearing, it has to pass the cam lobe oil hole. In theory it is possible to have damage only at your bearing surface without damage on your cam lobe due to a clogged lubrication hole at the end of the cam, or in a situation that there is just enough oil to lubricate the lobe thus oil not reaching the cam bearing surface (both very unlikely).

Well, it's up to you to decide what to do, and for clarity, a picture of the lubrication system of the CB450 K0 (the same as the CB500T), a copy from the Honda FSM:

 

[LongDistanceRider]

It's only applied to the external parts. Mainly because it's better hard wearing compared to paint, it doesn't discolour or chip off, easy to clean. My understanding is they have different formulas for different applications. Please checkout the their website for full information. https://chameleonvapourblasting.co.uk/

Ah, CeraKote was done rather than a actual ceramic coating. Great choice for the engine finish IMO. I did the CL350 in Satin Aluminum because it was a very close match to the original silver Honda used.

 

[JAY-CB500T]

My new eBay exhaust cam arrived today. The journals look to be in in good condition and within spec but I think I am measuring the cam height wrong or the service manual is wrong?? 4.65mm??

 

[ancientdad]

I just checked the 500T FSM and I have no idea what they're measuring with those specs. When it says "measure the height of each cam" it obviously isn't the total cam lobe height as you're ,measuring it, even if you move the decimal one position for centimeters it doesn't add up. The 21.958mm measurement is on the bearing journal which shows .009" wear according to the specs. A visual on the cam lobes condition would help, any significant wear would be visible as it's highly unlikely anyone would clean up and re-polish if t was just pulled from an engine (unless it looked hideous, and then the clean-up would be noticeable)

 

[JAY-CB500T]

I believe these are OK. Normal amount of wear you'd expect. Better than what I've got anyway. The followers are the ones that came from the damaged cam, so they must of been getting sufficient oil there.

 

[ancientdad]

See the light scuffing on the cam lobes? THAT is poor warmups right there, and given enough repetitions and time it becomes a lot worse, which is how people end yup with dished followers and very difficult to adjust valves.

 

[LongDistanceRider]

I think if you measure the base circle and subtract that from your lobe measurement you'll get the right numbers.
Rockers look good.
Cam lobes are scruffy. I would use a Medium Fine or Fine knife sharpening stone with lots of oil and gently work the surface of the lobes to smooth them out. Light circular motions and keep moving along the lobe never focusing on one section.

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[jensen]

4,7 mm is lift height, the difference between the 40.66 mm minus the base circle diameter, a google search first hit would have given you the answer, a picture makes it as easy as can be: B-A = C.




You wrote:

The followers are the ones that came from the damaged cam, so they must of been getting sufficient oil there.

And that's exactly why I wrote this:

Looking at the cam shaft bearing area, I'm still thinking that hard particles fit the damage, either beat particles, or hardened metal parts (bearing parts, gear parts etc). You're sure that beat particles are not the reason, the damage is due to hardened steel particles, either from other parts then the camshafts, or the camshafts themselves.

One other thing to mention, from what I can see in your pictures, the cam lobe, close to the bearing surface, looks very clean, and "unharmed". I have seen many damaged camshafts, and when the bearing is damaged due to oil starvation, the cam lobes will go first, because before the oil reaches the bearing, it has to pass the cam lobe oil hole. In theory it is possible to have damage only at your bearing surface without damage on your cam lobe due to a clogged lubrication hole at the end of the cam, or in a situation that there is just enough oil to lubricate the lobe thus oil not reaching the cam bearing surface (both very unlikely).

btw, You wrote "The bike runs sweet as a nut in my opinion", did you ever heard a good CB450 engine running ? I can't imagine because the cams in that state would be really noisy

I don't know if the bike did run like this, but your cam-follower shaft is pointing in the wrong direction ?

 

[crazypj]

If it was due to oil starving, I would expect to see blueish, golden area's on the cam journals. Also, the very "nice" straight grooves pointing to debris, blasting media residue or something else. I also never saw that stuff that's coming out your filter, could that be debris mixed with oil?

Like AD says, take it apart completely to avoid issue's in the future. I would try to find out what that "gunk"is, by solvng it in petrol and filter with a coffee filter. How did the filter element look like ? If this gunk went trough your filter, it probably found also the way into your crank.

Once I saw a cam with these kind of heavy damages, the engine was full of glass particles, and I mean, not the glass particles used by bead blasting, but solid particles of glass.

My thoughts exactly, blasting media in 'everywhere'
If it's your first major re-build it's understandable as you just would not know the people doing work didn't clean things out as well as you thought they would and you needed to re-do everything

 

[crazypj]

Possibly a question for a new thread but do you know of anyone who's done the Cappellini needle bearing upgrades to the camshaft bearings? View attachment 25888

They are stock parts bored for needle bearings.
If your in Devon UK, you can easily find a hobby machinist who can bore your covers and turn end of cam for the hardened sleeve, look up Model Engineers Workshop and maybe post a classified there (or the website, they have a motorcycle section)

Motorcycle General Discussion | Model Engineer & Model Engineers' Workshop

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www.model-engineer.co.uk

 

[JAY-CB500T]

4,7 mm is lift height, the difference between the 40.66 mm minus the base circle diameter, a google search first hit would have given you the answer, a picture makes it as easy as can be: B-A = C.

View attachment 25975


You wrote:


And that's exactly why I wrote this:


btw, You wrote "The bike runs sweet as a nut in my opinion", did you ever heard a good CB450 engine running ? I can't imagine because the cams in that state would be really noisy

I don't know if the bike did run like this, but your cam-follower shaft is pointing in the wrong direction ?

View attachment 25976

Thanks for the picture, yep that makes perfect sense now. Your right I cant say I've heard another CB450 or CB500T running sweet, all I mean by it running sweet it is it didn't sound noisy and it rode okay, don't recall any loud knocking while it ticks over.
As for the cam follower direction, this picture was a screenshot from a video, where I was purposefully turning the shaft with the screw driver to show the ends of the camshaft lifting up and down as the followers pushed the cam up. I know about the ticks pointing away from the sparkplug.

 

[JAY-CB500T]

My thoughts exactly, blasting media in 'everywhere'
If it's your first major re-build it's understandable as you just would not know the people doing work didn't clean things out as well as you thought they would and you needed to re-do everything

I am coming to the conclusion I will have to completely disassemble the engine again and physically push pipe cleaners or something down each oil way and remove any debris that might now be in the sump. I'm not a fan of doing things twice but it seems like the right thing to do.

 

[jensen]

You could drain the oil first, and filter it with a coffee filter. Then solve the residue in petrol and use a magnet to take out the magnetic particles, then use some enlarging optics for the rest to see what you're dealing with (alloy, clutch debris, rubber particles or foreign matter). Seems to be a lot of work, but gives you a good sense of what's going on in your engine.

 

[crazypj]

Something I have found very useful when re-building an engine that's been bead blasted.
Find the cheapest 5W or 10W engine oil you can get, start engine, run until warm, drop oil out and look for bits.
If 'clean', fill with 'proper oil' and change again after 150~200 miles.
If any bits come out, do it over with cheap oil.
In this situation, even non JASO car oil is fine, diesel probably better as it's high detergent.
Your trying to clean things not get max performance from oil and it isn't going to be in there very long

 

[JAY-CB500T]

You could drain the oil first, and filter it with a coffee filter. Then solve the residue in petrol and use a magnet to take out the magnetic particles, then use some enlarging optics for the rest to see what you're dealing with (alloy, clutch debris, rubber particles or foreign matter). Seems to be a lot of work, but gives you a good sense of what's going on in your engine.

I did change the oil before my last ride out, so it will be interesting if there's still debris on this oil change.

 

[JAY-CB500T]

So, with the intension now to do a re-build again. What upgrades or improvements are worth making to prolong the life of the engine? What is the best oil to use mineral or synthetic? Upgrade the oil pump? Upgrade the filter? Magnetic drain plug?
I fitted new clutch friction plates, refurbed the starter motor, new rings, new pistons, new timing chain and new seals. Are there any other parts prone to breaking that I should replace for the sake of it?
I also don't have the tach cable attached, would a left side intake bearing cover be better to replace it? I've seen this has been done before, maybe it'll allow the oil to flow better like the intake side?

 

[ancientdad]

So, with the intension now to do a re-build again. What upgrades or improvements are worth making to prolong the life of the engine? What is the best oil to use mineral or synthetic?

No need to spend extra money, many here including myself use Rotella T4 15w40 diesel oil as it has a higher level of zinc that helps with flat tappet engines.

Upgrade the oil pump? Upgrade the filter? Magnetic drain plug?

I added a couple of small magnets to my drain plug, secured with JB Weld, been in there 6 years with no issues, can't hurt though I find almost nothing stuck to it when I change oil and remember, mine went through an early grinding up of a follower and cam lobe so I must have managed to flush most of it in my efforts after the final repair. If you want an easy upgrade to the oil pump, VHT member Jays100 makes one. I'll be using one of his in my drag bike engine, but my red street bike has a stock oil pump in it so they can survive just fine when clean, maintained well and warmed up properly. But more oil flow can't hurt, especially if you're going to go through the engine again and it will have all new gaskets at the oil flow areas.

I fitted new clutch friction plates, refurbed the starter motor, new rings, new pistons, new timing chain and new seals. Are there any other parts prone to breaking that I should replace for the sake of it?

You should look closely at the shift detent mechanism if you pull it apart again, the large detent roller (aka pizza cutter) is prone to wear which causes the need for a second lift to get into 3rd gear from 2nd, and can cause only partial engagement which causes 'drop outs' from 3rd into a false neutral on deceleration at times, happened multiple times to mine during my first trip to the mountains in upstate SC in 2019. The 'star' detent on the end of the shift drum can get worn on the tips of the star and contribute to the problem too. This can all be done in the right crankcase cover and clutch area if the engine does not end up coming out of the frame. The pistons and rings should be good as long as they inspect okay, hard to imagine any debris getting to them though if bad enough anything is possible.

I also don't have the tach cable attached, would a left side intake bearing cover be better to replace it? I've seen this has been done before, maybe it'll allow the oil to flow better like the intake side?

It won't improve oil delivery, the tach drive cam bearing works just fine in that regard but id you do not plan to run a tach you can use a left intake cam bearing instead.