Have just bought a 1943 WM20 after only ever owned modern bikes for daily commutes so I see a lot of learning experiences ahead. Can any one describe the correct procedure to change the oil please. Apologies if this is. Bit simple for some but you have to start somewhere and I am quite keen not to experiment on such a well running machine.........

I change mine every 800-1000 miles or yearly if less, since a rebuilt engine.

I don't run with a filter in the tank. I get the engine warm and simply remove the drain plugs in the oil tank and bottom of crank case. I usually leave it to drain overnight before replacing with Morris's SAE 40. Ron

email (option): ronpier@talk21.com

I use my various old bikes as my main form of transport..

Like Ron, for the M20 I use Morris's Monograde SAE 40 with a change to SAE 50 if there is a very hot spell in the summer...The same oil grades from any quality manufacturer can be substituted for Morris's if you have trouble sourcing it..

A good quality 20/50 multigrade is also an alternative but avoid 'modern' grades such as 10/40, high detergent oils and ALL synthetics...

Also do not use hypoid gearbox oils for the box...These were designed to use engine oil..

SAE 40 is also the correct oil for the gearbox and primary chain cases in all conditions...

I have always changed oil at the 2000 mile interval recommended by BSA..Ian

email (option): ian@wright52.plus.com

I read this the other day on the Andover Norton website, I know it's talking about Norton Commando's but I thought the information was very useful. Note, the EP90 gearbox oil isn't suitable for some gearboxes but the rest is interesting.

Service Information- OIL

What oil for a Commando? One should have thought this is answered by workshop manuals and Riders Handbooks.

Unfortunately, this is not the case, as the oils recommended in these are not really suitable.

In production times Norton's first and foremost aim was to sell motorcycles. To do that they recommended not the oils that were technically best, but oils that could be bought at any garage.

This is the only reason why Multigrades were recommended. Friends from within the Lubricant industry, as well as Richard Negus, ex-Norton Motors "Chief of Motorcycles, and ex-owner & tuner of the most successful long distance racing Commandos, both confirm that, with the high temperatures combined with the high pressures in a roller-bearing engine, multigrade additives give up quickly and leave you with the base oil within as little as 600 miles- which means your 20W50 becomes 20 oil, which is not up to the job in a Commando engine used properly!

As for the primary drive, oils have changed dramatically since the early seventies, and additives we used to put into our engine oil, like STP, are now already contained in most multigrade oils. These additives are molybdenum (graphite) based, and will give you clutch slip very quickly.

We recommend:

Engine

Straight 40 HD Oil

Primary

Either a Monograde Oil, or (better) ATF Oil.
(I use Shell Donax TX)

Gearbox

EP90 Gearbox Oil

email (option): horror@blueyonder.co.uk

I just love discussions on oil!

I assume you just fill it back up via the oil tank. Does anything need to be done to ensure oil gets to all the places it needs to before starting it up again.

No! the oil is gravity fed to the oil pump. Just start the engine and let it tick over and watch for it to return to the tank via the scavenge side of the pump. Ron

email (option): ronpier@talk21.com

May I jump in on this thread? I am having trouble finding 40 weight non-detergent, but have found 30 weight non-detergent and 50 weight non-detergent. Is it acceptable to combine the two to get 40 weight, if 40 weight?

Thanks in advance

email (option): perryhq@frontiernet.net

Yes that is acceptable. But SAE 40 should be just as easy to buy as 30 or 50. I buy my Morris's SAE 40 from Mick Ash at £15 per 5 lts. Can provide his contact if required.

Ron

email (option): ronpier@talk21.com

It has been always my understanding that the only reason for avoiding detergent-containing oil in older motors is that, over the prior years of using non-detergent oils gunk accumulates in various places and, if you use detergent oil, that gunk will dissolve into the oil and cause damage; and therefore you can use detergent oil if the engine has recently been refurbished and such things as the oil pump, oil tank and sludge traps have been cleaned, then detergent oil may be used thereafter since there is nothing left to come loose. Is this understanding incorrect?

Second, in an engine with flat-faced solid tappets, like the M20-based family, fast-acting zinc additive is necessary in the oil, to avoid micro-welding of the cams. Is this not correct? (I.e., have I been wasting my money?)

email (option): jonny.rudge@verizon.net

Hi John...Your first point about detergent oils seems to be entirely logical to me...

On the broader question of the oil type used and what is best for these older engines I feel sure some more information would be useful...

Many of us use a 'modern' monograde such as Morris's or Silkolene mainly on recommendation, whilst actually knowing little, or nothing, about how those products compare to the original oils.

For example, exactly what additives they do or don't contain and the purpose of the additives that are actually present in the chosen product...

Does anyone know of any articles written by an oil producer that explain some of this in laymans terms?....Ian

email (option): ian@wright52.plus.com

This article is absolutely essential reading -

http://www.realclassic.co.uk/techfiles/oil030319.html

Gerry Bristow worked in the oil industry for many years and really knew his stuff. Sadly he passed away a few years ago so some of the oil brand references may have been overtaken but the basics are just spot on.

It's a common misconception that detergents loosen detritus in engines. They don't. The role of an oil detergent is simply to hold the microscopic particles in suspension ready to be collected by a filter (i.e. a proper car type filter).
Don't panic - detergent oils can't suddenly release giant sized lumps of abrasive grit!

email (option): njgreen@bigpond.net.au

I have been told few times, that multigrade are not recommended to use
On engines with roll-bearings on the crankshafts, because when the engine (And oil)
Is cold, the viscosity would by low (i.e 20 on 20W/50 oil) and not sufficient
For lubricating the roller bearings.

Now, when searching, I found this interesting article, which states:

"Multigrade oils are not recommended for roller-bearing crankshafts"
Interesting ..

http://www.classicandperformancecar.com/features/theknowledge/282575/the_knowledge_which_oil.html

Also interesting:

http://www.machinerylubrication.com/Read/204/multigrade-oil

http://www.classicmotor.co.uk/oil.htm

http://www.vw-resource.com/engine_oil.html (Air cooled VW)

Noam.

email (option): noam10@gmail.com

Nigel: Don't know about the rest of the article you reference, but Racing 4T oil is certainly not a re-labeled car oil. It meets more stringent specs than ASA, such as JASO MA. It's also 2-2½ times more expensive than regular synthetic.

Noam: Sorry, but a bare statement that "multigrade oils are not recommended for roller bearing crankshafts", without an explanation, does not convince me. What does he mean? Is this oil actually bad for those engines, or is he saying it's a waste of money because you don't need it, single-grade working just as well because of the lower native friction of roller bearings?

Informative thread but nothing here to make me give up my trusty 20W50.

email (option): jonny.rudge@verizon.net

Noam: Sorry, but a bare statement that "multigrade oils are not recommended for roller bearing crankshafts", without an explanation, does not convince me. What does he mean? Is this oil actually bad for those engines, or is he saying it's a waste of money because you don't need it, single-grade working just as well because of the lower native friction of roller bearings?

Informative thread but nothing here to make me give up my trusty 20W50.[/quote]

Hi John.

You are right.
Not a lot of information there regarding this subject.

The reason that I know about,
Is that the oil is not thick enough for lubricating roller bearings
(Especially ones that work under pressure and bangs, like the bigend)
When it is it its W20 state..

I also used the W20/50 few times.

Noam.

email (option): noam10@gmail.com

This article is absolutely essential reading -

http://www.realclassic.co.uk/techfiles/oil030319.html

Gerry Bristow worked in the oil industry for many years and really knew his stuff. Sadly he passed away a few years ago so some of the oil brand references may have been overtaken but the basics are just spot on.

It's a common misconception that detergents loosen detritus in engines. They don't. The role of an oil detergent is simply to hold the microscopic particles in suspension ready to be collected by a filter (i.e. a proper car type filter).
Don't panic - detergent oils can't suddenly release giant sized lumps of abrasive grit![/quote]

That is a very interesting article Nigel, and has come to the same conclusion I have with years of engine rebuilds and cock-ups with oil. It has made me more convinced that the synthetic oil I use is a good choice. Yes it's more expensive, but according to the write-up, will last longer, so balances out. As I've bored you all before about it, it's a 20/60w oil that's been made for roller bearing cranks. Rockoil TRM, it can also be used in the gearbox, but don't use it in the primary case or you'll make the clutch slip.

I got sick of seeing particles of metal in my oil every oil change and oil technology has moved on greatly.

http://www.rockoil.co.uk/cm/images/pdf/techdata/TRM.pdf

email (option): horror@blueyonder.co.uk

The only real conclusion that can be drawn from all this is that from a practical standpoint there is more than one oil type that will do the job perfectly well for most of us...

I've never run synthetics but have done very high mileages on SAE40 and 20/50W multigrades, in both standard and tuned engines...

I've never had an oil related engine failure, never knocked out a big end, never had a main bearing failure or experienced high levels of component wear etc. etc....

For example...After rebuilding it I did 79,000 miles on my 1951 B33 before I split the crankcase again...

Currently I see no reason to change my oil selection from the two noted above but appreciate other oil types may be just as effective...Ian

email (option): ian@wright52.plus.com

It's a common misconception that detergents loosen detritus in engines. They don't. The role of an oil detergent is simply to hold the microscopic particles in suspension ready to be collected by a filter (i.e. a proper car type filter).
[/quote]

Yes, and lots older bikes don't have a proper filter and are pumping the particles round and round. It seems logic to me that in that they will benefit more from the particles sinking down in the oil-compartment and bottom of the crankcase like it used to be when they were designed.

"Don't panic - detergent oils can't suddenly release giant sized lumps of abrasive grit!"


Well I think they can, I rebuilt a well used sloper engine en used 20W-50, the oil became black and full of grit almost instantly. It turned out that the oil was dissolving it from the bored balancing holes in the flywheels. I overlooked it because it was so hard it looked/felt like the metal itself. It was difficult to remove by hand but the oil had no problems with it.

When I worked for Harley Davidson and had to go on the training courses there was quite an emphasis on the type of oil to be used in roller big end bikes. Mono grade oil was recommended originally because of the bond of the molecules being broken down by the rollers in the big end was the main issue, however Harley themselves realised that mono grades weren't suitable for the large variety of operating temperatures that their bikes were subject to throughout the world, originally they recommended certain mono grades for certain expected operating temperatures. They went to great lengths to research which multi grade would be best to use in their engines and actually found that none of them would hold up, so they put a great deal of investment to formulate one that would do the job. Despite what people think of Harley's, they are still one of the few bikes that I see with quite large mileages and I used to see a lot of them that had done in excess of 100,000 miles, these bikes were usually dealer serviced with Harley oil, what was interesting if they came in with oil leaks and you actually got to see the inside of the engines , and I notice very little wear, usually just wanting a set of rings in them as the rings had become tired by this sort of mileage.
What I'm saying is that most oils will work quite well it's just how often you change it. Harley's oil changes are meant to be 5000 miles but most owners get it changed on every service rather than the recommended every other one.
I notice that if you keep the Harley oil in for the full 5000 miles the engine seems to get a little bit noisier but I give my Harley quite a hard life with hitting the rev limiter frequently and cruising at 80mph for long distances.

email (option): davmax@ntlworld.com

What oil is Harley oil Dave..? Is it a synthetic multigrade..?

email (option): horror@blueyonder.co.uk

I'm not sure as they keep it a secret, saying that it is blended especially for Harleys. I presume that it is a semi synthetic as they let you know that the different type of oil they use in the V rod is fully synthetic. The price of it compares favourably with other high end oils, as do most of the Harley service items. I use it in a lot of roller big end bikes that I'd prefer to fit a better quality oil into but I'm lucky I have a Harley dealer who sells this and also mono grade oil just down the road from me.
Dave

email (option): davmax@ntlworld.com