Oil, oil pumps and primary chains

[SteveD CB500K0]

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

[K2-K6]

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.

[Graeme77]

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?

[the-chauffeur]

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.  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.

[Graeme77]

Ok, a shim to make the tensioner apply more pressure.

Sounds ok, but must increase wear rates.

[K2-K6]

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.

[K2-K6]

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.

[Graeme77]

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.

[K2-K6]

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.

[Graeme77]

Its motorcycle oil, and should be ok for wet clutches, so im not expecting problems.
Might experiment next time though.

[the-chauffeur]

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 . . .

[UKROBK7]

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

[K2-K6]

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.

[ST1100]

...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?

[K2-K6]

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.