Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: Graeme77 on June 22, 2011, 08:41:41 PM
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Thought i'd put this is a new topic.
Continuing my 'rattle' issue, i dropped the sump pan and investigated a little.
First off though, the oil sitution seems a little odd to me. Im new to all this though.
I drained the oil cold (i know, but the petrol tank was off and i was impatient).
Oil tank dipstick read about 1" above minimum.
I drained about 2 liters of oil from the engine (didnt drain the tank).
How much oil should be in the case? Manual says 3.5 liters of oil for oil change, seems about right for my total, but shouldnt it be mainly in the tank, reading higher on the dipstick? Engine was last run last night for about 10 mins. Been run for about 10 mins most nights over the last week.
Next thing is the oil seems very thin to me. Clean though. Sort of single cream consistancy. Seems thin for either 10/40 or 20/40.
I dont know what oil is in it though. Smells a little too, not 100% sure if it smells a bit like petrol, but its a bit fumey. Possible for petrol to get into the case?
Was a little bit of crap in the pan, but nothing major. Looks like little bits of scraped off gasket, probably from previous rebuild. Nothing that concerns me too much.
I was going to pull the oil pump anyway, check it over. Make sure the check valve is ok etc. Any reason why i shouldnt?
Now, the primary chain. Took a measurement to the chain adjuster. 69.4mm. Got to love digital callipers 8)
JUST within spec. Ok to leave it for now? Its alot of wrk to change isnt it. Ok to leave it untill winter, maybe 1000 miles tops, or need doing now? Tensioner doesnt seem to have an awful lot of resistance/presure, pretty easy to pull back down. Ive no idea how much tension there should be though.
All looks nice up inside there though.
Thats more writing than i expected, so to sumerise...
1, distribution of oil between tank/sump ok, or odd?
2, possible for petrol to leak down?
3, primary chain, be ok for a bit, or do now!
4, oil pump, strip and check, or leave? Sort of depends on the answer to 1 really, is it scavenging properly.
Thanks :)
Wish i hadnt spent the last 17 years purely messing with cars now, might know a bit more about bike engines ::)
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Primary chain tensioner is not that strong it just keeps the slack at bay and slows down a bit of backlash nothing more. Sounds reasonably ok from your inspection.
The primary seems easily strong enough to take the strain from a standard motor and shouldn't give many problems. I believe it has a harder time if you were to thump it down through the gears as when the torque is driving the crank from the clutch then the tensioner is pushed out of the way so the chain can flap around (I guess if it was really too worn it runs the risk of trying to wrap round the crank in the above scenario) it's very rare to hear of a road bike have a problem with this though.
Petrol will get into the oil if you keep running it on choke, in my opinion it will also kill the engine (loss of protection for plain bearings and cam) if left like that so worth changing it asap.
I've always run 20/50 oil in these with no detergent addatives.
Oil system is a two stage dry sump. Scavenge lifts oil from sump to tank and there will always be oil in the sump pan or the pump would suck air. second stage of pump is fed a stable supply from tank and feeds direct to bearing system so should be maintained above minimum to avoid air intake there as well. levels sound about right I usually check this with the bike level and engine running.
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Hya Bro, when you say you got two litres out of the sump, is that just from undoing the sump plug?
Or did you take the oil filter and container off from the front of the motor and count the oil that came out of that too?
The whole system has a three litre capacity, and if you found two litres in your sump, then I would cetainly check out the check valve and pump.
These old girls have a dry sump system, Furthermore 10/40 oil is recomended. (those restrictors are pretty small for oil that is too thick on a winters day!)
Drain the oil tank, and give it a clean out whilst you are at it, this never hurts, especially if you suspect the oil of being dodgy or smelling funny.
Check the oil pump/ and or check valve out in a meticulously clean enviroment, do it methodically, and keep everything scrupously clean... Imagine your work area is going to be for a surgeon to operate on you, and you wont go far wrong!
Any probs, report back.. have you got a manual?
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;) in reguards to the amount of oil in the sump , i would say its just WET-SUMPING, as oil does get pass the oil stopper valve over a long period of time,if the bikes left standing, this is disasterous on old brittish bikes as it cant suck up the oil and blows the seals,but not a problem HONDA CB750,S they just suck the surplus back into the oil tank,i bet if you had warmed the bike up first you would not have had 2 litres of oil in the sump ::)
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Ok, thanks folks.
I have the chelmer? book and a copy of the factory manual.
Ill take the oil pump out while im in there and check it for good measure.
Ill leave the chain untill winter. Good news that, cant really afford to do it yet.
On a seperate note, i found a place selling primary chain and tensioner kits.
They described it as an 'simple to fit kit'.
I wouldnt call what is esentialy a complete engine strip simple LOL.
Ill strip and go through the engine in the winter when its off the road. Plan of powder coating the frame then too.
Fumjey oil from running on choke sounds about right, has only realy run on choke recently.
For future reference, if the engine has just been run the oil should read near the max on the dip stick right? With a properly working pump/check valve, how long would it normaly take to run down into the sump?
Ill clean the pump up, fit a new filter, clean tank and refill.
Thanks for the advice.
I havent took the filter off yet either. The 2 liters is a guess, but thats just from the sump. Sump plug was stuck solid (still is) so i just dropped the pan.
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Oil pump is out, check valve was stuck fully open.
I think the pressure valve was stuck too.
Not going to open it up, ive free'd up the stuck items so ill re-fit it as it is.
Need new O rings as the old ones are a bit flat.
Oil filter looked mank, but have 2 new spares. I even took the roll pin out of the oil filter bolt to make sure the little plunger was free. Dont know what it dos, but if it is supposed to move ive made sure it does :)
The 1 liter or so of oil left in the oil tank had drained out over the last 24 hours, luckily the catch can was still under the engine!
Tried to get the neutral switch out to check too, sometimes you put it in neutral but the light doesnt come on for a while. Figured the switch might be sticking.
Unfortunately the terminal screw is solid and rounded out and the 10mm bolt is stuck fast. Its soaking now, hopefuly ill have more luck tomorrow. Annoying that the frame is in the way, stops me getting any decent tool on it.
Speaking of O rings, anyone changed the one behind the counter shaft bearing holder, behind the gear change mech? Read on the other site that it helped the guy's problem of getting it into neutral when stationary.
The screws rounded out on him though, anyone else experienced this?
While im at it i might as well do all the crappy little jobs.
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I see most people like mineral oil rather than semi synthetic.
Are you finding mineral mitorbike oil, or just using normal car oil?
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Thought you would find something amiss with the check valve, I am glad you found the problem quick and sorted it out. Two litres was much to much to find in the sump!!
you say you have the clymer manual, watch out, for the Torque on the oil filter housing bolt, If I am remembering correct the clymer gives it as something reall y really WRONG, like ridiculously high...
You do not want to strip that bolt..
Be carefull with it, the correct torque is 20 - 24 ftlbs.
hope this helps.
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Tesco 10 w 40 mineral Diesel oil at
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Don't use car oil. Just Google it if you want chapter and verse!
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Still use Duckhams 20/50, change the oil and filter every 1000 miles. Although that Tesco oil that Bryan mentioned sounds interesting.
Cheers
Den
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Tesco 10 w 40 mineral Diesel oil at
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I'll stay out of the car oil debate, had a few arguments on other forums about it..... but do you have a link to the place selling primary chain and tensioner kits? They may be of interest to owners of the bikes that don't have one like the 550.
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Ill try and find the link again, but the 'kit' was just the chains and tensioner together, for the cb750.
Tesco diesel oil?
That'll be for cars then ;)
I did google about car oil but didnt find much, ill look again.
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Thought you would find something amiss with the check valve, I am glad you found the problem quick and sorted it out. Two litres was much to much to find in the sump!!
you say you have the clymer manual, watch out, for the Torque on the oil filter housing bolt, If I am remembering correct the clymer gives it as something reall y really WRONG, like ridiculously high...
You do not want to strip that bolt..
Be carefull with it, the correct torque is 20 - 24 ftlbs.
hope this helps.
Thanks, i tend to use the factory manual anyway.
My oil filter bolt has a 21m nut welded on it! Was pretty tight LOL.
Im not a big fan of torque settings anyway. The only things i torque are heads, flywheels, con rods, rockers, things like that. Anything else gets done how i want it done. I'd rather trust my experience, gut instinct and the feel of it on everything else.
I dont even torque clutch bolts :o
I guess alot of folk will laugh at that, but ive never had any problems in 17 years of re-building and modifying old engines, even on ones converted to turbo and running high PSI figures.
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I did google about car oil but didnt find much, ill look again.
This is a good one:
http://www.realclassic.co.uk/techfiles/oil030319.html (http://www.realclassic.co.uk/techfiles/oil030319.html)
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I've always run these 750 motors on the original Castrol GTX 20/50 car oil, this is from and in the 80s and never had any problems at all. None. This experience pre-dates any current discussion (pre-dates any of these forum!!) so I've not taken into account any current discussion.
I looked after a K6 in that era for a friend and this took an unimaginable thrashing that would truly make you wince but it never ever suffered any lubrication problems running on that oil never smoked, broke or stopped.
It's slightly odd after oil change as when you've put all the plugs/filter back on ten filled the tank with oil, as you start it the tank level will usually go down very quickly as the system refills via the oil pump so makes sure you have enough in the tank to avoid sucking air.
You can take the plugs out and spin it over with no compression at first if you want to be kind to it.
It's my opinion that mainly oil contamination by petrol has caused many petrol motors to wear prematurely over the years and have use of choke is a disaster to the general health. It's only to make it rich enough to fire and should be backed off ASAP and use higher tick-over to keep it running as this has no detrimental effect. I always smell the oil over any engines I'm asked to check as to me any smell of petrol means it's defective for it's principle purpose of lubrication.
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The link above seems to suggest car oil is fine.
It also says use multi grade,and that mono grades in old times were recomended because 'that was the bets available'.
Then, in another part of the site is says to stick with different single weight vicocities in different seasons.
Both in relation to nortons, but polar opposite conflicting opinions on the same site ???
All i want is to be able to go and buy it localy tomorrow morning and for the clutch not to slip LOL.
Looks like ill probably use halfords own semi synthetic 10/40, hein gerickes version of the same (i need to go get some grips anyway), or maybe this tesco diesel oil. Been searching the net for info but cant find any.
Can you tell us all a bit more?
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If you decide you want to start digging around inside the engine (and save yourself a few quid), you could do worse than the primary chain tensioner mod about halfway down this thread (http://forums.sohc4.net/index.php?topic=36459.msg943490#msg943490). I doubt you'll be able to do it without splitting the cases.
I did it when I put new chains in mine, and the engine now seems quieter than before, but then I also changed all of the bearings in the engine, so I'd bloody well hope it was quiet . . .
As for oil, the shop manual for the 750K series said 10w40 should be used in the forks - that should tell you all you need to know. Just bear in mind that when these engines were made, oil was oil - it didn't come cut with detergents and all sorts of additives - and those that were looked after have lasted pretty well.
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Ok, a shim to make the tensioner apply more pressure.
Sounds ok, but must increase wear rates.
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Looking at the tensioner "strategy" I feel that the spring rate applied can only really try to keep the chain reasonably quiet and stop undue stress from any uncontrolled flapping about, it's not very sophisticated else it would probably be damped as well.
If you think of the drive chain under load then with the tension run pulling the clutch basket all the slack will be roughly held in-check by the tensioner but nothing more.
If you then look at the chain under reverse load i.e. rolling along the road with the rear wheel turning the crank then all the slack will probably be on the opposite run with the tensioner pushed as far out as possible (200-300kg of bike and rider is easily going to push that spring rate) so it then has little or no effect anyway.
I don't see how we can argue with the original Honda design on this one unless you are particulary well informed on drive train analysis, so would choose to leave it as stock if no defects are present.
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On the oil issue. I've no experience of any synthetic in these motors so have no means of commenting on that one.
To me though any oil diluted with petrol is almost certain to be out performed by most new oils so whatever you put in now should help protect it better. If you change your mind then just switch it it's not going to be a disaster.
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Well, it now has halfords semi synthetic 10/40 in it.
Gearbox seems to go into neutral better now too.
Ill measure the oil pressure when i get it running better.
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It seems that the argument against car and synthetic oils in these is primarily the clutch slip potential, and if that is all there is then I'd consider it worth a test to judge it for yourself.
All the other properties of the oil you've put in are surely what you'd want to achieve so plain logic would go for it rather than against. Again it's not going to cost much if you decide against it, if a clutch problem is evident then stop and think again.
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Its motorcycle oil, and should be ok for wet clutches, so im not expecting problems.
Might experiment next time though.
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My experience is that moving from motorcycle oil to car oil isn't really that much of a problem. Moving from mineral to synthetic, however, is more problematic.
Having said that, the problem isn't lubrication; K2's right - it's all about clutch slip potential. As far as I can tell, the best way to care for the engine is to decide early on in the life of the bike what type of oil you're going to use - car, bike, mineral, semi-synth and so on. Once you've decided, stick with the same type, remembering the frequency of oil changes will be infinitely more important than which particular type oil you chose. Like K2, I tend to use car oil on the older bikes but for financial reasons; I change the oil far more regularly in my old bikes than I do in the modern ones (every 1,000-1,500 miles or so as opposed to every 3,000 odd) and if I was keeping to that sort of schedule exclusively with bike oil, I'd be bankrupt by now. I don't race, and don't put the bikes under any unusual loads, so that suits me fine.
If you decide to switch between oils, I've found the best way to reduce/minimise/eliminate clutch problems is to strip out the clutch when you switch and either replace the fibre plates (not cheap) and/or clean all the plates with thinners and let them dry. In both cases, soak the plates in the new style oil before putting them back into the pack. At least that way you've got more of a chance of them responding properly when you flush the engine with new oil.
The fun thing about oil is that you'll find pages and pages of stuff of the interweb, either in articles or across forums, and as many different opinions as there are drivers . . .
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Everyone has a favourite oil! I have used Castrol Power 1 10W-40 4T (motorcycle) oil in my bikes. This is what my local dealer uses when they service customers bikes. It's semi-synthetic and I've never had problems with wet clutches with it. They said never use fully synthetic or the clutch will slip
Rob
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A lot of the internet comment seems to ASSUME that synthetic and derivatives is mythically more slippery and I don't know if that statement is true.
My understanding of synthetic is that the long chain molecules (these are apparently the bits that keep your pristine metal bits from touching each other and hence prevent wear) are more stable, stay intact longer and under wider conditions i.e. heat contaminant etc still manage to perform the job over and above the ability of non-synth type oils, all the stuff by the oil companies seem not to claim it's more slippery.
The clutch is specifically designed to expel oil from between the plates (that's what all the little detail gaps in friction plates are for, to break the oil film when they come into contact with the metal plates)when you let go of the lever and, the materials are matched to that environment to operate effectively. I guess if you had any specific effect it would be in the time the clutch took to bite fully as the oil cleared.
If you take the demand of an air cooled four stoke engine into account I would say that the benefits for using synthetic are definitely there i.e. localised hot spots that are better managed with water cooling are potentially offered improved operation with a synthetic. Also things like the F2 cam area, and any of the later SOHC engines that run wth lean carbs and probably higher temps.
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...long chain molecules are more stable, stay intact longer and under wider conditions i.e. heat contaminant etc still manage to perform the job over and above the ability of non-synth type oils...
Exactly the arguments why I'm successfully running 5W60 fully-synth (MC17/EXS) in my 1100cc w/cooled touring rig since many years/miles now...
plus the points about better suspending abilities, friction additives, lower decomposition rate, chemical stability, etc...
So what are the opinions of using a 5W60 in a fully rebuild, air-cooled SOHC?
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I think that if I were in that position certainly it would be worth trying.
Couple of things give me a benchmark to go on.
1, car use. We owned an audi 5cyl petrol bought second hand direct from owner at 48000 miles which had been run from new on shell synthetic. We changed it to Mobil1 and ran it to 150000 miles (then sold) but you could look into the cam cover and still see the clean aluminium of the head plus the original grind pattern on the base circle of the cam lobes. the oil was always changed at 6000 miles intervals and came out a pale fairly clear golden brown i.e. similar to when it went in. It had no work other than service items during this time and ran fualtlessly, also revved to 7200rpm so not far off some of these old SOHC but longer stroke so could even have a higher linear piston speed than these.
2, Friend worked on military aviation jets and explained to me that as the oil used was not subjected to fuel contamination then there was much more detailed examination of oil performance as it virtually looked new although it would be at the end of it's performance life. This really showed me how dirty four-stroke motors make their oil from combustion by-products and degrade the oil.
From these I formed some opinions of my own about oil use. First is that combustion polutants get into the oil by going past the piston rings (specifically the top compression ring) and can be general blow by from poor sealing in normal use and much more blatant with extended use of the choke during warm-up.
The audi showed me that a well designed and good materials used engine, when run on synthetics had easliy almost nil wear over it's 150000 miles so a testemant to synthetics I think and certainly agrees with your use ST1100.
If you can get low wear from the start of your engine's life you will simply have less oil contamination anyway as you have not worn the piston rings/bores in the first place and so long term oil performance would always be less compromised. You'd probably have less need to change the oil any way.
IF there was an issue with the clutch, some sensible investigation (maybe use a stronger clutch spring to raise the clamping pressure) could deal with it.
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The long drain fully synthetic oil for trucks is now supposed to stay in for 180,000 Km YES YOU DID READ THAT RIGHT!!! before needing changing, which is good when its
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I ran the factory filled oil (whatever that was) for like 1000km/600miles in both bikes as well as in them cars, like as a 'brake-in oil' (very old fashioned I know ;), but it gave me some confidence), to then change filter and oil to my 'preferred' full-synth weight/type.
I did notice that all engines required a higher milage to finally 'free up', like 20Tkm/12,5Kmiles at least, while never showed any mentionable rate of oil consumption either, even after well exceeding the 100Tkm/60Kmiles (bike) or close to 300Tkm/187Kmiles (car, petrol engine); which would confirm lower friction, thus lower wear of parts due use of full-synth.
On cars I use 5W40, on the bike the 5W60 on which I frequently receive objections about using a higher grade then rated by the manufacturer (except from my well trusted mech, who's fully confident on that oil :D), but I think that since a motorcycle engine is driven way harder, I like to have some reserves; an issue maybe even more critical on them air-cooled, thus partially hotter running SOHC engines.
With the 5W60 I can further maintain a 'touring friendly' interval of 12Tkm/7,5Kmiles, instead of the 6Tkm/3,7Kmiles suggested by the manufacturer, due which I would not be able to make my runs without being grounded for 'overhaul' somewhere along, which also helps to make the of course higher price of this 'liquid-gold' more bearable as well ;D
I would however not extend the interval beyond this, over factors like shear and chemical contamination...
As with your Audi, also the guts of my engines are just 'sparkling clean', no sludge, no deposits, no sooth, just spotless, amazing me newly every time I wrench on them...
However have I been told that its not adviseable to change the oil type once an engine has been ran with a particular type (dino, semi, full) over a longer period, as such could lead to soften/loosing deposits that have aided sealing, leading to a previously not occurring oil consumption.
I also don't know how, or how much of it applies to the sinthered connection rod bearings?
Further will the plates of wet clutches have saturated with the used oil, which then might not work properly with the now 'new' oil there.
I'd actually experienced such once, as my mech was not avail once and they'd incidentally filled a 'standard' oil into my engine, causing the clutch to not fully disengaging, plus not properly engaging either... a look at the view glass gave it away then...
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I know this is somewhere adrift of the original post but has some very interesting points that are relevant.
The HGV stuff certainly puts us into perspective as regards longevity. As I understand it when you change the oil frequently what you are really doing is throwing away the contamination as opposed to the oil breaking down from it's normal operating function. This is why you should limit on choke running to as small as possible time to prevent just throwing petrol/combustion waste into the oil on these old bikes.
For years we've had oil spec for example rear axle of a car that has no polutants from combustion and no requirement to change them for the life of the vehicle.
I understand for new engines now one of the issues of running in is to get the bores and rings to seal properly and modern synthetics can prevent some of this process happening. If you accept that the rings when squeezed into the bores are not perfectly matched to the bore shape then, it's the action of the bore hone sharp edges that effectively "file" the rings into a best possible match and hence most effective sealing. Once the minute sharp edges are smoothed from the honing process then very little further improvement will happen, this is the reason for some very specific oil requirements for initial running and you also need to use the engine throughout a wider range than past convention would suggest. I believe some car turbo desiels suffer from high oil use later in their mileage if this is not effectively completed. In effect you initially at least have a conflict of promoting some ideal wear characteristics while still protecting the other bearings etc from any wear. This is also why you need an oil change so soon to throw out the tiny particals you've worn off the bores/rings.
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I must admit most new hGV have a centrifugal filter as well as paper element, as to the running in bit Kawasaki had a problem with the first 1,000cc fours in that a lot of UK riders were running them in to slowly and glazing the bores and they were being re-bored under warantee plus owners told to go out and use them properly!!
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Here's an interesting piece of information, from a Honda shop manual for 1978 covering american models K8 and F3 750cc SOHC (UK models K7 and F2).
It quotes for "oil specification"
HONDA 4 STROKE OIL or an equivalent.
API service classification; SE
Viscosity; General all temperatures SEA 10W-40
Alternate
above 15 C SAE 30
0 C - 15 C SAE 20 or SAE 20W
below 0 C SAE 10W
Nothing is stated about car/motorcycle oil.
I'd guess at anything in the 0W-to-5W range was not generally available off the shelf when that was written.
Also it states from new/empty fill 3.5ltrs and from oil change 2.5ltrs including filter/sump/oil-tank emptied.