Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: alexdecker on February 06, 2022, 12:14:25 PM
-
Hey
Took apart my top end today. Noticed some irregularities in the surface on the lobes and rocker arms. Attached some pictures. What are the standards for this? Still good? Not all of the wear can be felt with my fingers or nails - only some of it.
If not, do people usually get these fixed, or just buy new ones?
- Alex
-
What exact bike is this, early 500/550 cam covers can wear the rocker spindle holes oval allowing odd wear patterns.
Difficult to tell wear by pictures but if feelable wear you need different parts
-
This is from a 1978 CB550F. The wear is feel-able on some if the lobes and rocker arms…
- Alex
-
That should have the later cover with locked shafts which probably means lack of oil changes or wrong oil used.
Cams and rockers from any 500/550 are the same and earlier, unpined, covers will fit complete or provide internal parts.
You can get reprofiled cams but mostly from the states. Usually lots of used parts on fleabay.
-
Although the shafts can be locked, and yours are as I can see the pins, the shafts themselves can wear, especially if the oil isn't changed regularly. Pull the shafts and see what they look like. Be aware though that if they are worn they are very difficult to find and expensive when you do so. Get the cam reprofiled, might as well have a better profile while your at it, add 5 degrees of overlap and 10 degrees of duration. Get the rocker arms done at the same time or find good ones on Ebay.
-
I do indeed have the newer cover. Ok, so all agree that I need to do something about the wear? Damn. Gotta find someone in Copenhagen who can handle that then. US eBay (and also England since #@%$) is a no go for me :(
-
If I find a new cam shaft, I should replace all the rocker arms as well, right? Is there anything else I should be concerned about regarding the cam shaft? Does it need a new sprocket as well when replacing?
-
Only if it shows signs of damage.
-
I for one would happily act as middle man and resend parts as a "gift" to you. If rockers pads are in good order no need to replace, chances of finding a new cam at an affordable price is rare
-
I saw a NOS camshaft the other day on EBay, expensive though.
-
Ah, I was under the impression that they all had to be replaced at the same time, as they get worn together. Anyways, no matter as the rocker arms are worn as well, so will have to fix the whole bunch. There shouldn’t be trouble in reusing the rocker arm shafts, right?
-
I for one would happily act as middle man and resend parts as a "gift" to you. If rockers pads are in good order no need to replace, chances of finding a new cam at an affordable price is rare
Thank you! I’ll definitely keep you posted on that if the need comes :)
-
You need to check the rocker shafts, which you'll need to remove to remove the rocker arms anyway.
-
deberias de medir las levas , creo que los limites estan en el manual .
si no quedara otra opcion se pueden rellenar con soldadura , un tornero sabe hacer ese trabajo , aunque puede que ese trabaja ya se a echo , se ven poros en el metal
revisa los ejes
You should measure the cams, I think the limits are in the manual.
If there is no other option, you can fill them with welding, a lathe operator knows how to do that job, although it is possible that this work has already been done, you can see pores in the metal.
check the shafts
-
I saw a NOS camshaft the other day on EBay, expensive though.
I wrote with an eBay seller who is selling one that is new. He is telling me that the part number is 14101-323-000EH, but he is warning me that the cam shaft is only 27hp. I am not even sure what he means, as I have only been able to find one part number for the cam shaft in an CB550F (for all the CB550 actually), and his part number fits that.
Am I missing something here?
-
I saw a NOS camshaft the other day on EBay, expensive though.
I wrote with an eBay seller who is selling one that is new. He is telling me that the part number is 14101-323-000EH, but he is warning me that the cam shaft is only 27hp. I am not even sure what he means, as I have only been able to find one part number for the cam shaft in an CB550F (for all the CB550 actually), and his part number fits that.
Am I missing something here?
I know with the CX500 in Germany there were two different power options (perhaps due to some legislation in Germany) so perhaps that was the case in Germany on the 550. Even the 1st CB750 diecasts had German option on the pipes and were marked HMCB750 rather than HM300. Having said that I can find no reference to a lower power cam option in Germany in either parts books I have only on CMSNL
Uli on here (Sgt.Pinback) will probably know. Although the 27PS option is listed for USA ? ? :-\
-
compre un arbol de levas usado que este dentro de esta tolerancia , por que gastar tanto dinero en uno nuevo ?
como ya le dije un tornero puede reparar el suyo , ojo ! aqui hay otra errata , en vez de 35.85 son 34.85
buy a used camshaft that is within this tolerance, why spend so much money on a new one?
as I said a lathe operator can repair yours. see here is another typo, instead of 35.85 it is 34.85.
-
compre un arbol de levas usado que este dentro de esta tolerancia , por que gastar tanto dinero en uno nuevo ?
como ya le dije un tornero puede reparar el suyo , ojo ! aqui hay otra errata , en vez de 35.85 son 34.85
buy a used camshaft that is within this tolerance, why spend so much money on a new one?
as I said a lathe operator can repair yours. see here is another typo, instead of 35.85 it is 34.85.
I have no workshop in my area that provide that service, so that's why Im looking at new ones as well. I live in Denmark…
-
And part of the repair process will involve case hardening after filling/machining - so even more specialist/expensive
-
a pity, but it would surely cost much less than 1100 euros + taxes.
-
Surely there must be some camshaft repairers in Denmark?
If not send it to a UK firm along with the followers.
-
I've made some enquiries at Newman cams in the UK to see if they can reprofile my current cam, I'll let you know what they say and if they give a price.
-
I've made some enquiries at Newman cams in the UK to see if they can reprofile my current cam, I'll let you know what they say and if they give a price.
I already asked around a bit, but the one I found who could do it was really expensive - just about as much as buying a new one.
Thank you for that enquiry! Looking forward to hearing an answer - really appreciate the help an effort!
-
Send it to Newman Cams, they have reprofiled two cams and followers for me in the past. Good price, fast turnaround. Call them and speak to Mike Newman.
-
There you go Alex
http://www.newman-cams.com/
-
Got the reply from them today, they have quoted £100-120 plus VAT plus P&P.
Good price.
-
I presume that’s just a regrind and surface heat treatment?
-
That was a price to reprofile the cams, which is essentially the same as repairing the lobes.
I asked for an additional 5 degree overlap and 10 degree duration as per Mark Paris recommendations.
Additional information.
After emailing with Newmans the price for repairing the lobes is the same as reprofiling them, just wanted to confirm that. They are EXCELLENT at responding.
I also asked about journal wear, like scoring etc, these can also be repaired by hard chroming the journal and grinding it back down to size, cost is £40 a journal, even doing all 4 at £160 is cheaper than finding a NOS cam. Plus it would probably last longer so long as the oil problem that caused it in the first place is solved.
He did however say that the cam lobes must not be knackered, I presume by that not blued etc due to oil starvation where the lobe has virtually melted. I'm trying to get some clarity on what or how much damage is knackered.
Hope that helps those who want a cam repaired.
-
Admittedly I am no metallurgist and therefore my knowledge of surface treatments is somewhat limited but, I remember asking a question to a camshaft engineer a few years ago about surface treatments applicable to my Honda 400/4 camshaft as in would they case harden the re-profiled lobes to bring it back to standard. The response I received was Honda camshafts are made from chilled iron and don’t have any surface treatments?
I always thought the lobe of a cam is case hardened to prevent rapid wear or does ‘chilling’ cast iron produce the hardened surface? When I was at school we case hardened metal by heating it and dipping it into a tin of powered carbon (I think, it was a long, long time ago). I also thought a worn cam lobe is built up by ‘welding’ new hard wearing metal (stallite?) to it using a metal spray technique but apparently this isn’t always the case, some lobes are just re-profiled but this is something I just don’t understand, surely re-profiling will make the lobe smaller so how can it therefore provide the specified lift to the valve? This would especially apply to something like a four cylinder ohc, if one lobe is worn and re-profiled I therefore assume the remaining lobes will have to be re-profiled to match even if they are not worn otherwise one lobe will be smaller than the others?
Also, if the cam is chilled iron and therefore has a certain depth of case hardened material on its surface, how deep is the case hardening and will re-profiling the lobe go below the hardened depth?
Is the above the reason why Honda recommend the frequent oil changes they specify, to protect the cams that are not case hardened?
My head hurts now ???
-
Ken.
Can you expand upon the 5 and 10 please.
-
Shifting the cam timing like that shifts the torque peak to different rpm (usually upwards) with BHP a calculated number using rpm as multiplier, it appears to have higher BHP from the same engine.
It's an odd thing, as torque is what pulls it along but BHP is often used as the big headline number that people are interested in.
It will go faster as in rpm the minute component brings a time basis to performance in that you'd gear it down to rev higher and produce more power pulses over the same distance you travelled (that's effectively what BHP means, workrate in time stated) but probably with exactly the same torque as you had before.
What it means;- you'll have to run higher rpm to match or exceed the std one.
Look at torque for a current 600 and compare it to these 550, then look at BHP and the rpm difference to illustrate the above. At 14000rpm a modern motor is packing far more power pulses into each mile and so it's faster.
-
Wow, that price was better than I expected. I have written Newcams as well now :)
-
supongo que newcams trabajara en unos cuantos hondas esta temporada
I guess newcams will be working on a few hondas this season.
-
Phil, just say you want 5 degrees more overlap and 10 degrees more duration and let them worry about it. It's the way the lobes are profiled, overlap is the time both valves are open at the same time, duration is the time the camshaft holds the valve open.
According to Mark it really wakes up the 500/550 engine, there are other little things you can do like making a pocket above the inlet valve, they always say "Don't lower the floor, raise the roof", and raise the exhaust ports about 2-3mm and smooth the port out. That's to aid the flow of exhaust gases as they exit the engine.
-
Thanks, Ken. That’s exactly what I was looking for.
I’ve already ported the head…nothing drastic, just smoothing matching and a slight raising of the roof. Basic fluid dynamics stuff. I was going to fit a 650 cam, but the opportunity didn’t present itself, so your 5/10 comment piqued my interest.
Not looking for remarkable gains, but I used the rebuild to optimise what I have. I’m pretty sure it won’t be worth the time invested, but it kept me off the drink and donuts for a while😊
-
For reference, I got a quote for alle rocker arms + cam shaft for £420 all in all. That is quite a bit cheaper than buying new. Now I just gotta figure out how to ship into the country. Don't know what changed since Britain left in regards to shipping into the country, but it would seem that I could still save a lot by going this route.
Unless someone has a cam shaft and rocker arms they wanna sell me? :)
-
New cam and rocker arms?
Quote from Newmans by any chance?
Wonder what the cost of a ferry trip is? Pop over and pick it up yourself ;D ;D
-
Check your customs i think into UK repair parts are zero
-
For reference, I got a quote for alle rocker arms + cam shaft for £420 all in all. That is quite a bit cheaper than buying new. Now I just gotta figure out how to ship into the country. Don't know what changed since Britain left in regards to shipping into the country, but it would seem that I could still save a lot by going this route.
Unless someone has a cam shaft and rocker arms they wanna sell me? :)
los balancines no se ven mal
the rockers don't look bad
-
The rockers look knackered, and it's their surface that's been taking the cam apart.
It may be the pictures, but they're not good. I wouldn't put them near a new or refinished camshaft.
-
Ok , lo miraré de nuevo cuando encuentre mis gafas
Ok, I will look again when I find my glasses, where are they when they are not on my head?
-
It's the "strakes" ( the lines going in direction of cam travel)marking the rocker faces I'd be most concerned about, which is what they look like in the photos.
Ordinarily to wear the cam lobes you get pickup (lubrication failure under pressure) that cold welds one surface to another, this then acts as abrasive (on the rocker face) to wear the cam lobe as it goes round. It can also leave no tappet clearance at that point, which further destroys the oil film right the way round the cycle in that line. This is why it starts to leave that characteristic strake.
Ultimate cause is oil condition/quality, usually through fuel dilution as it's been run too long between changes.
-
Phil, just say you want 5 degrees more overlap and 10 degrees more duration and let them worry about it. It's the way the lobes are profiled, overlap is the time both valves are open at the same time, duration is the time the camshaft holds the valve open.
According to Mark it really wakes up the 500/550 engine, there are other little things you can do like making a pocket above the inlet valve, they always say "Don't lower the floor, raise the roof", and raise the exhaust ports about 2-3mm and smooth the port out. That's to aid the flow of exhaust gases as they exit the engine.
Thinking about this and follower geometry. It looks as though you could do this with a rocker geometry change, in that if you have the rocker pads refaced (Newman cams) and ground to a larger radius, then it would achieve the above overlap and duration with the std camshaft. You could swap them out to see what you preferred then.