Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: Murf on July 19, 2024, 12:29:05 PM
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The tensioner I have is knackered, the tensioner pad has wear and cracks and the tensioner arm had not been fitted correctly, it wasn’t in the pocket in the crank case. It has wear marks at the bottom which look looks like it was catching on the primary drive chain. The Drive chain looks undamaged.
Silvers have complete tensioner for around £145 + but I have seen just the pad part for around £50, what are your views on these options? Also is the original tensioner arm, not pad, even reusable due to the damage.
I realise that fine metal particles from this damage could have circulated around the engine in the oil, which I am not happy about but don’t want to strip and rebuild the bottom end.
I had the sump off when I first got the bike, it looks like it has been off and cleaned in the past, there was a small deposit in the sump under where the tensioner was catching the chain. I didn’t take much notice as I didn’t know of the problem at that point. The mesh oil pick up screen was very clean. I have attached Photo to try and show damage.
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That is bent due to incorrect fitting, you can, if lucky, straighten it but you need one to compare it to, put up a pic of the slipper for advice, getting a used tensioner is unlikely, i will be stripping a couple of 550 sometime in the next 6 months but no idea of condition
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I bought an aftermarket tensioner blade from Cmsl - it seemed more flexible than the original but that could be due to heat hardening of the ( slightly cracked ) original. It’s a critical area on these bikes and if I had my time over I would splurge on a new complete oem unit to be sure that chain noise is minimised after all the rebuild effort, though for now at least it’s quiet on mine. Primary chain is reputed to be the source of a lot of noise.
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Is this a 500 or 550?
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550K1 looking at earlier posts.
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Hi all and thanks for your replys, it is a 550K1, someone had done a top end overhaul before I got the bike, what a mess, the incorrectly fitted cam tensioner is just one of many cock ups which I am sorting out.
My question was about seeing what sort of new cam tensioners people had used and who the supplier were. David Silver does have them at about £170 inc vat, it does say they are from a good Japanese manufacturer, so I will probably go with that.
My intention is to do a good job and end up with a nice reliable bike I can use. I know it’s not going to be cheap.
DavidCumbria your thoughts about wishing you had fitted a full replacement are interesting and I think that is what I will do seeing as how the original has been damaged. I will have a search for suppliers.
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The primary chain problem is less on the 550 than 500, the crankcases are a different casting, primarily for the gearbox but i believe the main oil gallery in the lower case is slightly farther away from the chain.
The 500 frequently has deep gouge marks in the gallery where the worn chain eats into it and there are stories of actually wearing through, though personaly not seen one that bad.
The 550 still gets marked but not as bad, again in the ones i have seen.
The wear is bad enough and the bottom end normaly so reliable that if you split the cases you change the primary chain, especialy now we know a kawasaki one is the same at half the price
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Very easy to damage the end on the tensioner .. I thought I had damaged mine when I wrongly assembled mine last year but it turned out OK in the end. At the time Ken (Oddjob) who was on here had six spares ... pretty sure he must still have at least one.
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Maybe it has been asked before. About tensioning the camchain, does it make a difference if the engine is warm or cold?
Could a somewhat increased blueing of the headers indicate it's time to tension the camchain?
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No and No, blueing is probably single skinned aftermarket headers
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Hi
I am considering just fitting a new cam tensioner pad into the old tensioner to save a bit of money. CMSNL have oem one for around £90 and none oem for around £40, cheapest complete tensioner is around £180 at DS, any thoughts on what you would go for?
It looks like I also need to change my primary chain as well, so interested to know about the Kawasaki chain that is the same and half the price that is mentioned in the thread. Primary chains at DS are £69 +vat so about £81.80, CMSNL are more expensive.
Thanks
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The search function is your friend but i was board so Kawasaki 92057-1011
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Fowlers
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No and No, blueing is probably single skinned aftermarket headers
Thanks, Bryan. Exhausts are OEM. I never quite understood what causes blueing. A since long deceased racer once told me that when the headers blue, one way or the other, your firing is late. I'd like to learn more on this.
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Maybe it has been asked before. About tensioning the camchain, does it make a difference if the engine is warm or cold?
Could a somewhat increased blueing of the headers indicate it's time to tension the camchain?
It shouldn't make any difference that's measurable in the design used.
The "pull" side of chain going from camshaft to crankshaft has the dimension set from design (not altererd by adjustment) to facilitate correct timing always. The non pulling side feeding up,to camshaft from crankshaft, just has to be controlled by the provision of adjustment tomstop it flapping.
Pedantic and technical, chains aren't generally "tensioned" as the loading if they are will advance wear on the bearings etc used to support them. The spring in the adjustment mech is specified to avoid tightening too much, then to give a problem. This is the same for cam belt design too.
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No and No, blueing is probably single skinned aftermarket headers
Thanks, Bryan. Exhausts are OEM. I never quite understood what causes blueing. A since long deceased racer once told me that when the headers blue, one way or the other, your firing is late. I'd like to learn more on this.
Blueing, the ultimate temperature the exhaust material has reached (research "Kelvin scale" for detail) is affected by combustion temperature, obviously, but with many description not fully aware of what happens to do that.
The cam timing should essentially remain the same (as no adjustment is made to the critical distance in the chain pull run) which wouldn't give a shift in engine operation. If the camchain (very old) gets longer, then the intake valve would close later in crankshaft degree position, resulting in lower compression ratio dynamic effect. That would tend to cool combustion a little and be opposite of blueing. Toyota prius for example does this, using an Atkinson cycle engine config. By delaying the intake closed point, the piston coming back up the bore ejects some combustion gases back out the intake port, this lowers the effective compression ratio, gives cooler running, less internal resistance, and quiter combustion. Generally it won't rev fast though, so they use variable valve timing to facilitate "normal" running as revs climb. Kind of the opposite to Honda V-Tec arrangement, in which they operate at low speed in normal mild timing, then swap to wild camshaft timing at high rpm to give race type performance.
This affects the mechanical component of the combustion cycle, with ignition timing another aspect and overplayed onto anything happening here.
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I thought Blueing was simply the effects of heat cycles on the Chromed exhuast pipes, dependent on many factors such as ambient air temperature, exhaust gas temperature, exposure to chemicals in the air. Plus the actual design e.g. Single Skin.
It is the case that a lean mixture turns into hotter gases out of the silencer, a rich mixture results in a colder exhuast most noticeable at idle. I'm talking here about using the palm of your hand to measure the heat.
I would be guided by the colour of the spark plugs rather than attaching too much meaning to a blue manifold.
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Thanks gents. Would any of you guys know which model Honda was the first with a self-adjusting camchain?
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I thought Blueing was simply the effects of heat cycles on the Chromed exhuast pipes, dependent on many factors such as ambient air temperature, exhaust gas temperature, exposure to chemicals in the air. Plus the actual design e.g. Single Skin.
It is the case that a lean mixture turns into hotter gases out of the silencer, a rich mixture results in a colder exhuast most noticeable at idle. I'm talking here about using the palm of your hand to measure the heat.
I would be guided by the colour of the spark plugs rather than attaching too much meaning to a blue manifold.
I'm not sure I could touch my exhaust at idle, it is a Delkevic stainless system so single skin but still runs very how
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Not the manifold - you put your palm a few inches away from the tail pipe.
Handy on a 500 as it reflects individual cylinders thus carbs
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I've used a temperature gun on it, I get lower temps on the outer two cylinders.
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So 1 & 4 are a tad too rich - try opening the respective air screw an eighth of a turn out?
That said heat dissipation from the outer cylinders will be better than inner ones so it might be bob on.
Plug colour might be a better guide.
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The exhaust gas temperature would likely only be reliable for jetting under full load, not at idle. I dont feel you'd need to respond to that in this scenario.
This probably is a topic on it's own rather than in a camchain thread.
The reason to vary idle mixture screws one to another is well established by Honda setup routine though. Theres nothing wrong with doing this.
Effectively, their setup routine specifically tells you to do that on a cylinder by cylinder basis. By turning screw out to go lesser until it fails some firing events tells you where air fuel,parity is for that cylinder. Then it instructs you to turn the screw back in again until you make a 100rpm drop in crank speed. That sets the individual cylinder to its optimum ..... given the prevailing hardware, fuel used etc.
What this achieves is parity of combustion at the tickover rpm to facilitate smooth running and set the "gain" or slope response for the idle circuit to bring the engine up into running on main jet and needle.
Also,, its the fine detail that people THINK is sole responsibility of carb synchronization routine, which doesn't have the fine resolution to enact this part.
An intrinsic part of production setup from Honda, and why they are rarely a match for idle smoothness post that time.
I've noted before, but this is exactly what modern fuel injection system do to give those ultra stable idle, measuring crank speed and trimming cylinder fuelling to smooth out the peaks. Automated yes, but essentially the same as this old setup.
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The reason to vary idle mixture screws one to another is well established by Honda setup routine though. Theres nothing wrong with doing this.
Effectively, their setup routine specifically tells you to do that on a cylinder by cylinder basis. By turning screw out to go lesser until it fails some firing events tells you where air fuel,parity is for that cylinder. Then it instructs you to turn the screw back in again until you make a 100rpm drop in crank speed. That sets the individual cylinder to its optimum ..... given the prevailing hardware, fuel used etc.
What this achieves is parity of combustion at the tickover rpm to facilitate smooth running and set the "gain" or slope response for the idle circuit to bring the engine up into running on main jet and needle.
Also,, its the fine detail that people THINK is sole responsibility of carb synchronization routine, which doesn't have the fine resolution to enact this part.
[,,,]
I wonder if that setup routine was maybe prescribed for twins, where I can understand it can work well. I have my doubts where it concerns our Fours. My CB500 carbs lack acceleration jets and I like to think of the slow jets as auxiliary jets that happen to double as idle jets. Across the pond they still believe in plug chops at idle. From experience I can tell you, it won't work, not on a CB500. Either I have plugs with the ideal color and poor acceleration, or I have a good acceleration and black plugs if I idle too long. Anyway, decades ago, without having read anything on it by Honda, I got the idea myself. In practice it didn't work. Also it is very, very time consuming, I can tell you, as you have to wait at least 20 seconds after each minor adjustment step and there are many steps... I judged the method as typical a theoretical thing from the books. So far I have not seen a video that could convince me. That is: I can't remember I have ever seen it demonstrated on a Four.
If one is lucky to have a 4-4 exhaust, one could try by comparing the sound at the end of each pipe and fine tune the airscrews until each pipe produces the same sound. To avoid the gasses, one could use a rubber hose like a stethoscope. Would be nice if we could arrive at a recording of the right sound for reference. And also which sound indicates a too rich and which sound indicates a too lean setting. I was told experienced professional mechanics, familiar with our models, could do the adjustment by ear.