Post by: Erny on October 18, 2020, 09:25:22 PM
Preparing for engine opening and partial or full rebuild. As I’ll do it for the first time, I’d like to kindly ask for forum experts’ advices/recommendations. I’ll keep thread updated as I’ll proceed. Sorry for long post in advance 😉
Bike is stock CB550K K1, has 17.7k miles total. Engine pulls good as far as I can judge (till 70 mph good, above it not so fast, max speed is about 90-100 MPH)
So let’s start with why I plan this and what I want to address/achieve:
1. Issue with either camshaft or valve rocker or something else – so need to open valve cover as minimum, more details here http://www.sohc.co.uk/index.php/topic,23227.msg208693.html#msg208693. Along with that I want to replace valve cover by new type, that have fixed rocker arm shafts. But need to find it first. Along with that of course new gasket.. Optionally, if it turns out that camshaft needs to be replaced, I’ll try to find one with improved torque or one from CB650. And of course rockers if replacement needed
2. Rattling noise @idle coming from head-cylinders (pushing clutch makes just little difference). I’ll make video and post it here, maybe you know that noise and its route cause. Bike idles well, ign. set properly, carbs synced
3. Cam chain replacement
4. If head will come off – complete head work – cleaning, valve checks, eventually new valve guides, seals, check for flatness / milling … simply taking opportunity that head is off, check/replace all needed. All gaskets / O-ring / seals replacement. Check/replacement of tensioner
5. If cylinders will come off – replacement of piston rings. I expect bores & pistons will be OK
6. Splitting cases is big question now – I’d like to fix shifting issue, but still hope this could be caused by mechanism under clutch (?) http://www.sohc.co.uk/index.php/topic,19775.msg175185.html#msg175185 On the other hand side, having cylinders off, maybe it is good idea to replace all seals, primary chain and check gearbox (?)
Now first questions – before I pull engine and start stripping, any advice what I should do before?
I’m thinking about:
- leak test (to estimate rings / head status to be confirmed when removed)
- redo compression test to have reference for comparison after rebuild. Last measurement was: dry: 120/120/110/130 psi, wet (teaspoon oil into each cylinder) : 150/150/145/145 psi
- detailed inspection of clutch and shifting mechanism under basket – maybe after that case splitting not necessary (?)
Any thoughts / ideas / advices what else I should do before pulling engine / stripping?
Post by: philward on October 18, 2020, 09:34:28 PM
Post by: Nurse Julie on October 18, 2020, 09:38:59 PM
Post by: Bryanj on October 18, 2020, 10:02:39 PM
Post by: Erny on October 18, 2020, 10:24:18 PM
I will watch with interest Erny.thanks Julie, I hope Trigger will give some advice ;)
Post by: Nurse Julie on October 18, 2020, 10:31:38 PM
I'm sure he will Erny.I will watch with interest Erny.thanks Julie, I hope Trigger will give some advice ;)
Post by: paul G on October 19, 2020, 07:42:11 AM
;D ;)I'm sure he will Erny.I will watch with interest Erny.thanks Julie, I hope Trigger will give some advice ;)
Post by: deltarider on October 19, 2020, 11:47:44 AM
Bike is stock CB550K K1, has 17.7k miles total.To me the operation sounds a bit premature. These bikes were considered not to be fully broken in before one had 10.000 km on the odometer. Yours has 17.7k miles only.
When I had opened mine in 1987 and taken the engine to a mechanic for the measuring etc., first thing he said, was: why did you open it? I had no clear answer and I hesitated to tell him that at around 40.000km, I already had the camchain and tensioner renewed. Now, at around 80.000 kms - I had guessed - it would be about time again. I mean, what did I know? And let me also confess an amateur like me, had felt it a challenge to open up the engine, out of curiosity, just by following instructions the Haynes manual gave me. Not that that particular manual proved very helpful as it doesn't even cover the four rocker arm shafts lay out my model has. BTW, there are plenty that never had a problem with the eight shafts and to my surprise they are even found on the CB550K2 (76) up to engine number 1083640!
The mechanic commented he had seen CB500s that had done much more kms before an overhaul. I had taken the engine to him because he had a good reputation, had been a Hondadealer for decades and I didn't want to invest in measuring tools etc. anyway. Tools I'd probably use only once in my life. Also... a small sticker on the rear fender indicated the bike was first sold by his business in 1977. He had seen quite a few CB500s that had done 150.000 kms with just prescribed maintenance. BTW, in my archive, I have an article about a guy who had bought his CB500 new, rode it daily (summer and winter) and at the time of the article had done 220.000kms in 20 years with just the sceduled regular maintenance.
Anyway, here are the parts that were replaced: pistons (standard size) including pins and rings. Gasket set. Camchain and tensioner. Two rocker arms. Four exhaust tappets and their guides. Four spark plugs. I don't know if all these replacements had been necessary, meaning they were at their minimum. I don't rule out he had calculated that now the engine was open, it was a sensible thing to do in advance. I collected the engine, fitted it in the frame again. Now did I experience much difference? Mwah, not much more than before when I had renewed the spark pliugs. This is to warn you to have modest expectations about the outcome. We seem programmed this way: if I do this or as soon as I've bought that, things will be much better. In other words: somehow we are programmed to project an ideal outcome. So, I don't know if you know an oldtimer that has seen a lot of these bikes in his career as a mechanic. I'd ask him for a second opinion.
About the clutch. Although yours is different from mine, they're easy to work on. By the time I had to renew my clutch friction plates and springs, they had exactly reached the minimum Honda specifies in the Service Data chapter in the Shop Manual.
Why the CB550Ks have been not as fast as the CB500s, I don't know. My guess is increased weight and a different gearing have to do with it. All CB500/550s however should manage a top speed of 160 km/h+. On the Dyno mine reached 185km/h, but that was without winddrag ofcourse.
I now have 40 years of experience with my bike. Here a few things I have learned. 1) Plugcaps and leads are always the first to be suspected. 2) Our bikes don't particularly like nowadays gasoline. Years ago I used a fuel system cleaner (Tunap) for the first time. The result was phenomenal. It felt like the engine was reborn. And there was this nice rustle again I had dearly missed for so long. I'm still in the process of finding out what 'maintenance dose' of what is best.
A lot has been posted about engine oil. I prefer an oil that sticks to the camshaft somewhat (better for cold starts) over superduper full synthetic oil that will simply return a 100% to the crankcase, once the engine is stopped. The oil I use is not specific a 'motorcycle oil' whatever that may be. For a JASO oil the weight percentage of sulphate ash should be 1,2% maximum. That 1,2% happens to be exactly what Castrol specifies for the oil I use and since I have never experienced a slipping clutch, I see no problem in continuing to use that oil. I don't worry about the engine. I am quite tall and have therefore pulled the rubbers from the footrests to have a slightly better riding position. After all these years I still feel no vibrations there whatsoever. Not more than 40 years ago.
If you allow me a question. Like mine, yours has the beautiful 4-4 exhausts. I'm still not content about the way I have fitted them (left side). Sohron and Ashimoto have helped me a lot with their directions. Right side seems to be OK. Although... I still wonder, should the ten bolts that hold the oilpan all be accessible for a straight pipe wrench? Can you have a look what the situation is at yours?
Oh, I almost forgot. Make a good sound recording of your engine running, post it and let the experts here comment.
Post by: Erny on October 19, 2020, 09:05:23 PM
Post by: deltarider on October 20, 2020, 11:12:18 AM
I can not for the world remember, how it was when I first acquired the bike and I still wonder if bikes left the assembly line with all ten oil pan bolts perfectly accessible. Let me say that I have my doubts. Maybe others will chime in.
Post by: K2-K6 on October 20, 2020, 11:32:00 AM
Obviously doesn't comment on exhaust alignment, but useful nonetheless.
Post by: deltarider on October 20, 2020, 12:15:03 PM
Post by: Trigger on October 20, 2020, 01:46:31 PM
Post by: Erny on October 21, 2020, 10:27:57 PM
Please somebody to advice on my first questions – before I pull engine and start stripping, any advice what I should do before? (Trigger maybe?)
I’m thinking about:
- leak test (to estimate rings / head status to be confirmed when removed)
- redo compression test to have reference for comparison after rebuild. Last measurement was: dry: 120/120/110/130 psi, wet (teaspoon oil into each cylinder) : 150/150/145/145 psi
- detailed inspection of clutch and shifting mechanism under basket – maybe after that case splitting not necessary (?)
Any thoughts / ideas / advices what else I should do before pulling engine / stripping?
To provide more about current engine "noise" at idle - here is short video I made today https://youtu.be/9CKtENPWWDY, interested for your comments
Post by: Bryanj on October 21, 2020, 11:31:23 PM
Top end can be done with engine in, apart from that every time you open a can you find more worms
Post by: Erny on October 21, 2020, 11:38:05 PM
Post by: Bryanj on October 22, 2020, 01:28:28 AM
OK take the sump off and see how much play is on the primary chain, you can also get a finger in to see if it has been rubbing the oil gallery. 550 is not normally as bad as500 but can still hit if worn.
Post by: Trigger on October 22, 2020, 08:08:24 AM
Compression seems good but, a test is no guarantee on on a engine this old, just look at Julies thread and the state of her pistons and that had good compression, started on the button first time everytime :o
Post by: deltarider on October 22, 2020, 09:07:04 AM
Post by: Erny on October 22, 2020, 10:29:14 AM
Shall I also do it as dry and wet (spoon of oil into each cyl) ?
Post by: Bryanj on October 22, 2020, 05:28:40 PM
Post by: K2-K6 on October 23, 2020, 11:37:54 PM
As mentioned already, difficult to fully appreciate remotely but the audio if anything seems fairly clear playing it here.
If you video it the same agian but stand it on the ground and in first gear, then let the clutch out until it only just starts to bite. This may give an indication (if it goes quieter) of primary drive noise as it will tension it rather than oscillate.
It'll be interesting to hear if you get any change to the noise.
Post by: Erny on October 23, 2020, 11:42:32 PM
Post by: K2-K6 on October 23, 2020, 11:47:40 PM
OK, I can test this weekend and post here, so warm up, engage 1st gear, pull clutch that is starts to move bike, right? Will be difficult to have 3rd hand but will try ;)
Fix camera pointing at bike, first gear not to drive along but only just get the clutch to start dragging but brakes on. Should pre-load transmission and tension primary drive just enough to take out "flip flapping" would show if the chain is worn if noise gets less.
Post by: Erny on October 25, 2020, 10:42:07 PM
Engine warm-up made (approx 8km):
1. Idling + test of noise change after gear#1 enagage:
you can clearly hear that idle is not 100% regular, there are moment engine rises revs, even I felt during ride on low RPMs like engine running on 3cyl only occassionally... This is new behaviour to me. It feels like I ususally feel after bike washing (I did 1 week ago), engine does not rev more than 6k (feels like ign issue)
- time 0:08-0:15 - clutch fully pushed
- time 0:28-0:36 - clutch fully pushed
=> Rattling seem dissapeared
- time 0:58 - backfire (pipe#2?) - this happens to me for the first time, probaly linked to cyl#2 too rich (as was unable to fix that since long time|
Video here: https://youtu.be/gwZVUlbaXo4
Plugs after removal - photo attached
Seems like rattling comes from worn primary chain?
2. Compression test (hot) - made after idling test above on warm engine. Using kick start only
- dry test : 130/125/115/125
- wet test : 150/145/160/145
the same strange behaviour of cyl#3 observed during cold test (dry/wet)... what It could indicate? Rings issue?
Honestly I'm not sure about quality and capabilty of my tester, during kicking gauge arm is jumping up/down, see video from wet cyl#2 test
https://youtu.be/ROmpTSJdKIU
3. Before reassembling tank back, I left engine idling to burn oild from cylinders and raised idle - seems rattling is reduced / dissapeared. Smoke from pipes is white }condended water as enogine cooled down meanwhile)
https://youtu.be/lmlRuv11XtM
Note: I start to suspect something with coils/HT cables/plug caps (new in 03.2019) due to that irregular idle. Ignition is Boyer, so no points, no mech advancer
Anyhing else I should do before engine disassembly?
Post by: deltarider on October 26, 2020, 06:56:44 AM
... even I felt during ride on low RPMs like engine running on 3cyl only occassionally... This is new behaviour to me. It feels like I ususally feel after bike washing (I did 1 week ago), engine does not rev more than 6k (feels like ign issue)Without having studied the rest of your post, this phenomenon is classic for a CB500/550. These bikes have always been praised for their overall reliability with one exception: plugcaps and plugleads especially in rain. Also: when was the last time you've checked the resistance there? You could start with checking the total resistance from one plugcap via the coil to the other plugcap. Realise that new resistor plugcaps are around 5kΩ each. The coils secundary itself is around 14-15kΩ, so with both plugcaps attached, you should read 24-30kΩ in total. When you read over 30kΩ in total, unscrew both plugcaps to be tested individually. Over time the plugcap's resistance tends to increase. When over 8kΩ, replace. Do not run and resistor caps and resistor plugs. When you have the choice, I'd prefer resistor caps over resistor plugs. Verify plugcaps are firmly connected to the wires and there's no arcing. Be aware this may occur intermittently. It's best seen in the dark.
Post by: gbjeppm on October 26, 2020, 08:47:19 AM
After doing that to my CB550K it quietened down considerably.
Post by: Erny on October 26, 2020, 09:01:05 AM
Post by: deltarider on October 26, 2020, 12:24:28 PM
BTW, I love the sound of that repro set!
* Having seen Ashimoto's technical gear in his thread (Alladins cave) reparing his coils, I wonder what electronic parts one needs to build a device that can switch 4A at up to let's say 170 Hz. I'd like to build that, if it's not too expensive.
Post by: Bryanj on October 26, 2020, 01:03:55 PM
Post by: Erny on October 26, 2020, 01:12:17 PM
But first (and this is topic of this thread) I need to fix mechanical issues:
- camsharft/rocker issue
- potencially address lower compression issue
- rattling noise - primary/cam chain, tensioner
- gear box issue
Note: as pointed by K2-K6 an Trigger, stuck sprocket carrier does not "help" primary chain, so this needs to be addressed too.
Post by: Bryanj on October 26, 2020, 01:36:00 PM
Post by: Erny on October 26, 2020, 01:43:03 PM
Post by: K2-K6 on October 26, 2020, 03:06:52 PM
In view of the cush drive possibly being stuck as recently discussed, I would be inclined to work on the wheel first as it can have quite an effect on gear change quality.
If you open it, the cases, and can't find any internal problems with the gearbox, it will leave you not knowing what could be wrong. It would be extremely useful to you for diagnosis to make sure the wheel is as good as possible first.
At least you can be sure you've eliminated the cush drive. They can have a surprisingly large effect for something that doesn't appear to do much.
Certainly you can re-test and see for yourself if you feel a significant change without touching the engine.
Post by: Erny on October 26, 2020, 09:54:16 PM
Post by: K2-K6 on October 26, 2020, 10:23:15 PM
But certainly there's one way to find out, if you are going to inspect and assess the cush drive anyway it's just the order you'd do that in which may help you to evaluate the gearbox condition prior to deciding to dismantle.
Post by: K2-K6 on November 02, 2020, 01:13:04 PM
- leak test (to estimate rings / head status to be confirmed when removed)
- redo compression test to have reference for comparison after rebuild. Last measurement was: dry: 120/120/110/130 psi, wet (teaspoon oil into each cylinder) : 150/150/145/145 psi
- detailed inspection of clutch and shifting mechanism under basket – maybe after that case splitting not necessary (?)
Any thoughts / ideas / advices what else I should do before pulling engine / stripping?"
I feel that around 130 psi dry and warm is realistic for these engines to require no urgent intervention in correcting it via rebuild. Get down below 125psi and it's getting closer to making that decision. They run remarkably well below that with no real risk or issues, but unlikely to make full power. So it's not a drastic mechanical condition, more an overall understanding of where it is.
Saying that, the numbers and noises you've posted just seem very typical of one of these, not much wrong really but desirable to plan longer term to eventually correct with rebuild.
Why would the psi readings be like that? Likely from bore glazing and perhaps light cylinder corrosion during storage with the possibility of one or more valves being left open. Again, it's not drastic, but clearly it's present. Oil to test normally seals the rings during the test and confirm imperfections in sealing pressure.
Rattle that dissapears when loaded, more or less confirms extended wear of primary drive chain along with primary drive rubber being stiff through ageing.
Backfire and rough running, suspected leak from HT circuit (your observations about being like this after getting wet) and needs looking into to prevent. Possibly the plug caps or water penetration where it attaches to lead.
With this ignition they all fire ALL of the time, so it won't missfire from crossover HT leaks. But as two plugs are on one coil (all these sohc systems) then if only one plug cap leaks HT, if that route to earth is low resistance it also can stop it's "paired" plug from sparking. That leads to excess fuel in the exhaust of both cylinders, which will then backfire when spark is re-established.
It seems a characteristic of the fully electronic Boyer that at low rpm the risk of igniting in exhaust is raised IF there is unburnt fuel in the pipe, but the original fault is that HT leakage that causes the fuel to get there in the first place.
Concentration on fixing HT leak should remove this problem, and help with rough running.
Post by: Erny on November 02, 2020, 01:25:43 PM
I checked HT leads and plugs - measured both are bit above 24kOHMs on both coils (with caps on leads), so should be w/o issue.
Additionally, I replaced carbs by 069A set with 40/100 jets (rebuilt by Gerben), issue with dark plug No2 dissapeaded. Even engine is now smoother, pull nicely from 2000 till 9000+ rpms linearly (better than before). But I have to say I spent quite some tim syncing them, and still did not reach satisfactory (to me) result, each time I snap trottle, it behaves bit different. Sometime idle rpms are lower sometime higher. Strange
Of course, rattling is still there and I still need to fix that IN rocker issue on cyl 1.
So, next I plan leak test and open valve cover with engine still in frame. Will keep reporting progress
Post by: K2-K6 on November 02, 2020, 01:58:57 PM
The cylinder is drawing vacuum against the carburettor slide as restriction/resistance, this is indicated to you on the dial as to how much the piston going down the bore can lower the pressure below atmospheric when measured against a fixed constant (probably a spring and plunger in the gauge) and so give you a number to aim for and adjust the slides to give parity across the cylinders.
BUT, you've got one cylinder that aggregated measures lower than the other 3 because it doesn't seal correctly. By extension, that cylinder will most likely impart LESS vacuum to be measured through it's stroke as it has effectively less restrictions placed on it (carburettor slide as restriction/resistance PLUS it's leaking) which in pure vacuum measurements forces you to lower the slide to observe parity on the gauge. Which of course is correct for absolute vacuum numbers, but not for combustion. It effectively causes you to set that throttle slide lower than the others to get the readings correct.
This is wrong for the combustion equalization of the cylinders (some of the rattling is because each cylinder doesn't input the same energy into the crankshaft so that it's rotation is more staccato) what it needs is the throttle slide to be more open than the others to make that cylinder equal the other three.
Worse than that, the error as i'd view it is doubled. The cylinder with low compression already inputs less energy into the crankshaft, setting the throttle slide lower (to achieve parity of vacuum) also adds to that error making the idle more erratic, not less.
To compensate you'd need to set the other three to parity on the gauges, and LESS (this is what modern sequentially fired ecu injection systems do to maintain smooth idle) vacuum on this compromised cylinder, which should improve idle smoothness, but could compromise higher rpm performance.
An aggregated carb setting for synchronisation would be accurate bench synchronisation and not use the gauges so as to avoid the prompted wrong settings of absolute vacuum readings. It wouldn't fully compensate at idle, but would leave more accurate higher rpm performance alone.
Post by: K2-K6 on November 02, 2020, 02:50:28 PM
When new, the primary drive chain has fairly limited slack which keeps the driven components (clutch and gearbox internals) at more or less the same speed.
They are however a "remote" flywheel as they impart their own own constraint on speeding up the crankshaft when unloaded (idling and not driving the bike) and by nature fairly unsophisticated for noise insulation.
If the crank speed oscillation frequency arrives through a worn primary chain then these oscillations effectively keep transferring their difference in inertia by variously putting the slack in the opposing chain runs to keep then exiting the whole system which we hear obviously as unwanted noise.
If the engine running doesn't deliver equal pulses for each firing stroke it simply gets heard as more noise as it ricochets through the mechanical system.
As you raise crankshaft speed toward 1500rpm the primary chain centrifugal forces (effectively tensioning the chain) overtake the inertia from firing pulses, in addition the the firing pulses frequency rising above a point at which the flywheel natural frequency is exceeded cause the whole system to go quite. None of the faults disappear but just become harmonious.
Post by: Erny on November 02, 2020, 10:52:35 PM
Some thoughts on syncing that you could consider as it's one of sequentially imposed conditions that I believe can lead the wrong way.
The cylinder is drawing vacuum against the carburettor slide as restriction/resistance, this is indicated to you on the dial as to how much the piston going down the bore can lower the pressure below atmospheric when measured against a fixed constant (probably a spring and plunger in the gauge) and so give you a number to aim for and adjust the slides to give parity across the cylinders.
BUT, you've got one cylinder that aggregated measures lower than the other 3 because it doesn't seal correctly. By extension, that cylinder will most likely impart LESS vacuum to be measured through it's stroke as it has effectively less restrictions placed on it (carburettor slide as restriction/resistance PLUS it's leaking) which in pure vacuum measurements forces you to lower the slide to observe parity on the gauge. Which of course is correct for absolute vacuum numbers, but not for combustion. It effectively causes you to set that throttle slide lower than the others to get the readings correct.
This is wrong for the combustion equalization of the cylinders (some of the rattling is because each cylinder doesn't input the same energy into the crankshaft so that it's rotation is more staccato) what it needs is the throttle slide to be more open than the others to make that cylinder equal the other three.
Worse than that, the error as i'd view it is doubled. The cylinder with low compression already inputs less energy into the crankshaft, setting the throttle slide lower (to achieve parity of vacuum) also adds to that error making the idle more erratic, not less.
To compensate you'd need to set the other three to parity on the gauges, and LESS (this is what modern sequentially fired ecu injection systems do to maintain smooth idle) vacuum on this compromised cylinder, which should improve idle smoothness, but could compromise higher rpm performance.
An aggregated carb setting for synchronisation would be accurate bench synchronisation and not use the gauges so as to avoid the prompted wrong settings of absolute vacuum readings. It wouldn't fully compensate at idle, but would leave more accurate higher rpm performance alone.
It makes sence what you wrote.Let's see what I find when I open valve cover and what leak test will show
Post by: Erny on November 02, 2020, 10:53:39 PM
Going on to the noises made while idling.
When new, the primary drive chain has fairly limited slack which keeps the driven components (clutch and gearbox internals) at more or less the same speed.
They are however a "remote" flywheel as they impart their own own constraint on speeding up the crankshaft when unloaded (idling and not driving the bike) and by nature fairly unsophisticated for noise insulation.
If the crank speed oscillation frequency arrives through a worn primary chain then these oscillations effectively keep transferring their difference in inertia by variously putting the slack in the opposing chain runs to keep then exiting the whole system which we hear obviously as unwanted noise.
If the engine running doesn't deliver equal pulses for each firing stroke it simply gets heard as more noise as it ricochets through the mechanical system.
As you raise crankshaft speed toward 1500rpm the primary chain centrifugal forces (effectively tensioning the chain) overtake the inertia from firing pulses, in addition the the firing pulses frequency rising above a point at which the flywheel natural frequency is exceeded cause the whole system to go quite. None of the faults disappear but just become harmonious.
this is completely clear to me. Bad is that to replace primary chain I have to split cases ::)
Post by: deltarider on November 03, 2020, 06:39:07 AM
Post by: Bryanj on November 03, 2020, 07:34:05 AM
Post by: K2-K6 on November 03, 2020, 08:22:40 AM
Personally I find it hard to believe you'd have to replace the chain with 17.7k miles total.
I can see this view in normal circumstances, but if it is worn then that is factual. However it got so worn in the recorded mileage is more open to conjecture.
From Erny's point of view, I simple inspection through taking the sump off would give confidence as to the need to replace and the work involved, or not.
Post by: Bryanj on November 03, 2020, 08:28:30 AM
Post by: K2-K6 on November 05, 2020, 09:35:20 PM
If you don't verify the cush drive in rear wheel is ok (thinking in regards to gear change quality) and then try the bike to assess the affect it may have, then if you take the engine apart and the gearbox all appears ok, what would you do?
Put it back together without finding "the" fault, or change components at random.
Also for idle quality and smoothness, I'd set the carbs with the "compression weak" cylinder at less vacuum than the other three to listen and assess if it gives a noticeable change.
I just feel that would give a clearer picture and more knowledge to work from if you determine to strip it later.
Post by: Erny on February 18, 2021, 11:50:59 PM
Issue No1 (camsshaft/rocker arm) (see my first post for details)
Today I removed valve/cam cover to check IN#1 rocker
What I found surprised me (!?)
- IN rocker arm #1 has uneven wear (arm was touching cam only partially), at least half part of contact surface is not showing any wear at all. Seems issue is present since new bike >:(
- Cam IN#1 lobe shows strong wear (pitting incl) where arm was riding. Rest of contact surface does not show any wear
- Deeper inspection revealed issue comes from worn outside rocker arm shaft hole! Hard to believe but yes...
- Comparing how "deep" are shafts for IN#1 and othher shafts (EX#1, IN#4, EX#4) "buried" in valve cover, I found IN#1 is approx 2mm "deeper". Route cause comes from IN#2 shaft too "deep" and consequently IN#1 shaft too deep too that finally meant too narrow seat.
Shafts are all OK otherwise (forgot to take pics), incl IN#1. There does not look to be any issue with engine lubrication, all other cam lobes, cam bearings, rocker arms shows minimal wear I think (see pics).
[attach=1]
[attach=2]
[attach=3]
[attach=4]
[attach=5]
My conclusion is that issue is present practically from new bike, camshart to be repaired/replaced, rocker arm to be replaced, valve cover to be replaced, ideally with new improved type
Issue No2 (identified in previous posts here are probably worn primary chain)
I removed oil pan, see video of primary chain. Looks worn too much or not?
https://youtu.be/a1k28x_15lQ
Now, question to experts here:
- I assume cam lobe shall be repairable (hardwelding, grinding), but when I have it open, I'm thinking about alternative cam (something like Web Cam 358a or cam from CB650?) - what's your view on these cams and their effect on riding? Repair of my cam won't be for free anyway (if I find somebody to do the job).
- how to inspect cam chain and tensioner properly, having removed valve cover? Or, do I need to remove head/cyls too?
This will drive my next steps - if I'll continue stripping or "just" fix cam/rocker issue.
Post by: Erny on February 18, 2021, 11:52:18 PM
[attach=1][attach=2]
Post by: Bryanj on February 19, 2021, 12:26:50 AM
Post by: Erny on February 19, 2021, 08:57:19 AM
Post by: K2-K6 on February 19, 2021, 09:22:57 AM
Initial rough check of camchain;- just try to lift the chain at the highest point on the cam sprocket as it compares the chain pitch with the tooth pitch. Any more than approximately 1mm and it's worn to excess. Meaning that a new one cannot ordinarily be lifted, 1mm and you'd consider planned replacement, 3 to 4mm definitely finished.
Tensioner, again a rough first impression of if it's adjusted, turn the crankshaft backward 1/2 turn and check for slack on the front chain run if you can access it. An old bicycle spoke may allow you to just hook the chain to pull it back toward the rear of engine to assess if there's too much play. Or make a little wire hook to do this.
It really gives just a first impression of anything wrong. The cam chain lasts quite well though but obviously you'd change it if you did the primary one.
Post by: Erny on February 19, 2021, 10:57:53 PM
What about primary chain? Based on video and your experience, is it possible to say of chain is on its end of life?
Post by: K2-K6 on February 20, 2021, 09:05:17 AM
The limits for this engine are particularly, that it will end up touching the crankcase casting, and that it will make more noise when idling.
This one is not so urgent that you'd have to stop using it and change immediately, but certainly to plan for work to get the parts and complete when convenient for you.
As Oddjob says, the cush drives need to be considered if you are stripping to change the chain.
Post by: Erny on February 20, 2021, 10:47:33 AM
Post by: deltarider on February 20, 2021, 11:45:36 AM
(Courtesy Spargeljo)
Post by: Charlie J on February 20, 2021, 03:06:23 PM
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Post by: deltarider on February 20, 2021, 04:43:28 PM
Here is how I see it. Before I entered the internet, I had never heard of the primary chain causing problems, not from Honda mecs nor was it described in Dutch and German magazines.
Don't get me wrong. I am not denying the chain can eat in the crankcase. After all I myself once discovered an aluminium chip in the oil. When? Some 70.000 kms back... And there are also lots of photo's to prove it. You can make life easier for that chain by having the ignition timing even for 1+4 and 2+3 and the carbs balanced so that all 4 cylinders work as equal as possible.
So, would I replace that chain when the engine is opened? Definitely!
Would I open the engine just for that? No.
Post by: Bryanj on February 20, 2021, 05:01:17 PM
Different countries have riders with different riding styles as Yamaha found out with the RD350LC when after extensive testing they sold it to UK riders who promptly kept blowing exhaust gasket causing, i think, 4 different modification "kits"
Post by: Charlie J on February 20, 2021, 05:11:48 PM
Post by: Bryanj on February 20, 2021, 05:24:53 PM
Post by: Erny on February 21, 2021, 04:51:39 PM
Initial rough check of camchain;- just try to lift the chain at the highest point on the cam sprocket as it compares the chain pitch with the tooth pitch. Any more than approximately 1mm and it's worn to excess. Meaning that a new one cannot ordinarily be lifted, 1mm and you'd consider planned replacement, 3 to 4mm definitely finished.
Checked using proposed method (I did not released tensioner) - practically cannot lift it or just very little, but can move left/right easily (holding it at the highest point).
So, I would say chain is OK?
Post by: K2-K6 on February 21, 2021, 05:31:58 PM
It doesn't matter if it's tensioned or not as you are effectively comparing the chain pitch with the sprocket pitch, with no realistic slack it shows it's virtually as new.
A chain can be tensioned as much as possible, but if worn you'll still be able to pull the links away from the sprocket at the centre of it's engagement. If you can't it's definitely good.
They move/slide slightly side to side, all seems fine.
Post by: deltarider on February 22, 2021, 12:19:58 PM
Post by: McCabe-Thiele (Ted) on February 22, 2021, 01:58:40 PM
Post by: Trigger on February 22, 2021, 07:05:27 PM
Erny, your finding doesn't surprise me. On the German site camchains are often found not worn.
The Germans must ride about like Old men.
Out of the hundreds of SOHC/4 engines i have fully rebuilt i have only found a couple of cam chains that had minimum ware. It is still a false economy in my book as, a STD DID cam chain is only about £20 and will last at least 30,000 miles. That is about 66p per thousand miles and when most owners of classic bikes only do about a thousand miles a year, that is a lot of years from a chain ;)
Post by: robvangulik on February 22, 2021, 07:46:26 PM
You are aware that Germany is the only land in Europe, if not the world, where still are roads where it is legally possible to ride full throttle?Erny, your finding doesn't surprise me. On the German site camchains are often found not worn.
The Germans must ride about like Old men.
And I know from experience that most German bikers aren't afraid to do so.... :)
Post by: K2-K6 on February 22, 2021, 09:22:44 PM
Obviously, the problem with the rocker shaft and it's effect on running brings that to urgent scheduling, but cam chain is ok and primary serms medium worn and so not absolutely required immediately if may be better to complete next winter.
As already noted through the thread, camchain replacement is entirely sensible whether bad or not, if the crankshaft is coming out.
Clearly the two chains wear at very different rates, but then they are completely different engineering solutions compared to each other.
Post by: deltarider on February 22, 2021, 09:47:29 PM
TBH DR I don't think a lot of chains are worn, it's more to do with economy, whilst the engine is down it's false economy NOT to change the chain.I agree. I just said that Erny's finding didn't surprise me, having seen the findings on the German site. I didn't suggest not to replace it, once the engine is open. I'd do it and every mec in the trade does, even when the chain is not worn. What I'm afraid of is that readers will open up engines for the wrong reason. Actually the best video's I've seen about rebuilding CB's are by Germans. Very thorough (gründlich), very detailed.
Riding like old men? The Germans? You must be joking. It's the only country on the planet, where they have no national speed limit*. At 140 km/h one can hardly keep up with... local traffic.
*Which is a shame actually. Friends in Germany have informed me that this is because of a strong lobby by carmakers like M-B and BMW.
Post by: Erny on February 22, 2021, 11:54:20 PM
Collateral info - bearings in valve cover are perfect, cam does not show wear on bearings.
From my point of view they do not look very good, hoping you will say it is normal wear (17k miles?)
All 4 bearings on pictures here
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Post by: Bryanj on February 23, 2021, 03:21:34 AM
Post by: Erny on February 23, 2021, 07:43:47 AM
Post by: K2-K6 on February 23, 2021, 12:51:41 PM
To take it underneath that which is needed for good mechanical condition, it can tell us more about the conditions during running so far.
The outer two bearing surfaces show just a flattening of the original boring marks and exactly as you expect to find as witness marks.
The marks are consistent with the design in that the bore size has to have a tolerance in relation to the camshaft journal that avoids seizure and allows for oil film effectively not under pressure. You can see from the wear marks how far up the "wall" of the bearings that the two depart and no longer touch each other.
The centre two bearings show their witness marks travelling further than the outer two, a little like judging plastiguage. Meaning the camshaft has worn into the bearing further on these two, but a very very small amount.
This would happen if the oil film was unable to support the load as it should. Mostly this is associated with oil condition and specifically dilution/service interval in the engine's life so far.
It seems consistent with the amount of wear in the primary chain too. Those bearings (within the chain) are possibly the highest loaded individual parts in the engine with their lifing giving a good indicator initially of running conditions to that point.
As first stated, it's perfectly normal to see the bearings in the head like this and it's not a fault as such in the overall condition, just that you can have more of a picture of progress so far in the engine's life.
Post by: Erny on February 28, 2021, 12:26:28 AM
Took carbs and pipes off and did again leak test under these conditions: measured cylinder was in TDC, input pressure ~22psi as per leak tester manual.
result - all cyls:
- shows approx up to 10%-12% leak
- all IN and EX valves are tight (no air or sound goes off intake or exhaust port), air is leaking and is audible around cam chain and oil dipstick, so leaks past the rings (?).
With great weather over last days, I started to consider changing strategy - just fix valve cover, cam and rocker issue and keep riding bike this seson as is. Rebuild (partial or full) can be done next winter.
Before putting bike back to road, I'd like to test oil pressure - where people connect manometer to measure oil pressure? What fitting / tool I shall look for?
Post by: Bryanj on February 28, 2021, 12:38:04 AM
For oil pressure either remove the pressure switch and screw an adaptor in there or you have to drill and tap the hexagon "bung" below the points cover
Post by: deltarider on February 28, 2021, 07:17:15 AM
... or you have to drill and tap the hexagon "bung" below the points coverWhy drill? Can't you just undo it with a wrench?
Post by: K2-K6 on February 28, 2021, 09:14:32 AM
I can't see any problem with that. With the rocker fixed it should be fine and you'll just be planning an "advanced" service to change primary chain etc when it's convenient for you.
Oil pressure, can you temporarily install one of the car type gauge into the pressure switch port? Then you can measure it when it's fully warmed and running throughout rev range.
Post by: Erny on February 28, 2021, 09:22:48 AM
What level of pressure is minimum needed or which level is "good" enough?
Post by: K2-K6 on February 28, 2021, 09:30:39 AM
Post by: Erny on February 28, 2021, 04:09:38 PM
One more question - can I consider replacing vavlve seals w/o removing head? I guess it is doable but maybe difficult and special tool to support valves from bottom needed?
Post by: Charlie J on February 28, 2021, 05:13:35 PM
I used a Sealey VS1542 Valve Collet Remover/Installer to remove the valve springs so I could replace the oil seals without removing the cylinder head. I was a bit apprehensive about using it as I had read some reviews that said the tool was fine for removing the collets but not so good at reinstalling them. However, the tool worked a treat for me. The only slightly tricky part was dealing with the exhaust valves on cylinders 2&3 because of the proximity of the posts for the fuel tank mounting rubbers. But a sharp tap, square on with a 2lb hammer did the trick. I also used the string down the plug hole and rubber band tricks which I read about on this forum.
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Post by: Bryanj on February 28, 2021, 06:32:27 PM
Post by: K2-K6 on March 01, 2021, 12:16:45 PM
Thanks
One more question - can I consider replacing vavlve seals w/o removing head? I guess it is doable but maybe difficult and special tool to support valves from bottom needed?
Good first hand experience from Charlie there. I've not changed any with head installed so just an irrational, perhaps, fear for me, but would leave them if you have no signs immediately of needing to change them.
If you've confirmed the valves aren't leaking and happy with that, then caution in doing something that may just bend one even slightly (touching a piston crown with one edge) may be a more secure route. And eventually you'll get them easily if you do further work.
Post by: Erny on March 01, 2021, 12:31:26 PM
I assume seals will be hard after 46 years so not sealing properly I guess
But I'm only investigating now what are options/way to do. If too risky/complicated or costly, I'll let it be
Post by: K2-K6 on March 01, 2021, 01:03:55 PM
But through observation of an engine showing oil use I generally seperate as, smoking under acceleration consistently then its normally rings, with longer run (downhill) with throttle closed, then emitting smoke just when you open the throttle (single cloud) is ordinarily inlet valve guides as it sucks oil down the valve stems (high vacuum in inlet tract) to be burnt just as you open the carbs again.
Good idea to make a list of concerns that you can then work through later.
Post by: Charlie J on March 01, 2021, 03:20:45 PM
Charlie
Post by: Erny on March 01, 2021, 03:36:10 PM
Certainly I think Charlie's first hand experience out weighs my view, so doesn't appear a big risk.
But through observation of an engine showing oil use I generally seperate as, smoking under acceleration consistently then its normally rings, with longer run (downhill) with throttle closed, then emitting smoke just when you open the throttle (single cloud) is ordinarily inlet valve guides as it sucks oil down the valve stems (high vacuum in inlet tract) to be burnt just as you open the carbs again.
Good idea to make a list of concerns that you can then work through later.
This is something I do not know as I'm riding most of the time alone. Even when riding with some mate, nobody reported me any blue smoke behind me, at least not while accelerating.
When having bike on stand, I did not observed blue smoke while playing with trottle.
Estimated oil consupmtion is 0.5-0.7L / 1000km as I do not have it exactly measured. Most oil is burned after longer day-long trips (speed partially over 75-80 mph)
Post by: deltarider on March 01, 2021, 05:06:54 PM
Post by: Erny on March 01, 2021, 05:17:32 PM
Post by: K2-K6 on March 01, 2021, 07:32:11 PM
Nothing to worry about IMO. Realise that the oil 'consumption' you have, may partly due to unnoticed small leakages. The oil drain screw and the shifter seal are notorious for this. After I switched to Castrol GTX High Mileage 15W-40, which is known for keeping the rubbers supple, oil consumption has been reduced.
I don't think you'd be able to stand next to it without slipping over if it was leaking 0.5 litre every 1000kms ;D
At that rate though, I'd suspect ring and bore sealing primarily.
It'll keep the pipes nice inside though :D
Post by: Erny on May 25, 2021, 10:41:46 PM
I was considering several options, first was partial/full rebuild as discussed here (to replace primary chain too), later in order to save season just to fix minimum - valve cover, cam and rocker. For that I bought another cover (new type with 4 non-rotating shafts), megacycle cam 126-00 (for street use) and planned to install it instead of stock one to have better torque. Soon I realised I need slotted sprocket too for proper engine timing etc. (ordered, not arrived yet). Delays were just cummulating :(
As time was flowing, new season arrived fast, I decided quicker solution to save this season 2021 - get my original valve cover, camshaft and rocker repaired and install all back as it was till now. So, repairs done - cover with 2 bronze bushes, worn cam thumb grinded equally and re-nitridated, rocker grinded and re-nitridated. Cam and rocker done by proffesionals, looks like new after that. Of course, cost, don't tell me ::) ::) we all know...
Along with that I looked closer to carbs (022A, pilot #38, main #100) that since beginning were not perfect (kinda rich, especially 2nd cyl). I found emulsification tubes (especially on cyl#2) are quite worn inside (corrosion), main jets were not Keihin but aftermarket ones). Fixed that with aftermarket tubes (Keyster) and replaced mains by Keihin 100. Bench synced them (stell balls).
Assembled back, all regular service operations done too, all works now, bike idles very well and regular (like never before!), even no need to adjust sync by gauges.
However I observed another unpleasant behaviour, hopefully something I can fix with your support - I'll make new thread for that.
So, for this moment, at least this summer season, rebuild is put on hold, spares are waiting in the shelf ;)
Bike already tested on the road, I was even photographed 8)
It again confirmed to me that I love this bike!
Post by: philward on May 25, 2021, 11:02:21 PM
Post by: Laverdaroo on May 26, 2021, 11:04:33 AM
Post by: Laverda Dave on May 26, 2021, 11:59:19 AM
Of course you know that now the bike is running just as you like it when the slotted cam wheel arrives it will just sit on the workshop shelf as an expensive ornament :o
Post by: Erny on May 26, 2021, 12:03:32 PM
. I have never enough power and torque 