Castrol Classic 20w-50 Engine oil

L.A.B. said:
Well, as I said GTX 20w/50 isn't available in the UK.
www.castrol.com

Castrol GTX | Car oil & fluids | Castrol UK & Ireland

Castrol GTX is a premium conventional engine oil that clears sludge and prevents new sludge formation. Find out more about our unique formula.
www.castrol.com www.castrol.com

I currently use Morris 20w/50 Race V-Twin not that I ever race.

Race V-Twin 20w-50 (Formerly V Twin 20w-50) 4 Stroke Oils Motorcycle - Morris Lubricants

Leading UK manufacturer of world-class lubricants and associated products. A Tradition in Excellence since 1869
morrislubricants.co.uk morrislubricants.co.uk
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The world is funny today. BP owns Castrol but doesn't sell it in the UK. Best I can tell the oils in the link you provided are not sold in the US.

Best I can tell, your Morris oil is not available here except on eBay.
 
marshg246 said:
The world is funny today. BP owns Castrol but doesn't sell it in the UK. Best I can tell the oils in the link you provided are not sold in the US.

Best I can tell, your Morris oil is not available here except on eBay.
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My main point was that as olympus lives in the UK then what's available in the US or elsewhere is irrelevant if it's not available here.
 
One interesting fact is that the factory reverted to recommending monograde oil in July 1973 as stated in Service Release N3/59 but that 20w/50 multigrade was still alright to use.

Castrol Classic 20w-50 Engine oil
 
I get very nervous when the oil I’ve been recommended gets battered on this forum😰
Castrol Classic 20w-50 Engine oil
Castrol Classic 20w-50 Engine oil

Jim seems to really rate it, so do you lot know better? I’d really like to know 🫣
 
Café au Lait said:
I get very nervous when the oil I’ve been recommended gets battered on this forum😰View attachment 120183View attachment 120184
Jim seems to really rate it, so do you lot know better? I’d really like to know 🫣
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It’s Castrol themselves that put the cat amongst the pigeons…

They say this:
“suited to vehicles from around 1950 to 1980 that require a mineral multi-grade oil. It should be used in vehicles fitted originally, or retro-fitted, with a modern style spin-on oil filter. It is also suitable for later classic motorcyles, but should not be used in bikes with roller main bearings (these require a monograde)”.

It’s the alleged unsuitability for use with roller bearings that’s the issue. I personally think they’re talking bollox !
 
Café au Lait said:
I get very nervous when the oil I’ve been recommended gets battered on this forum😰View attachment 120183View attachment 120184
Jim seems to really rate it, so do you lot know better? I’d really like to know 🫣
Click to expand...
I have also used this product in British bikes for many years (without any known issues) and when ordering up for an oil change i came across the comment under the more info tab., i also highly rate the work carried out by Jim on the many different oils tested and graded.
But it doesn't get away from the fact that clearly noted on the Castrol web page it states not for use with bikes on roller bearing mains
As my machine isn't used through the winter, I'm now considering using Castrol 40 monograde
 
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I think there is far too much overthinking involved. I have a good friend who - around 15 years ago - rode from central Mexico down to Tierra del Fuego, then up to the North Slope of Alaska and then back to central Mexico. When he needed oil he bought "whatever the local grocery store had on the shelf." The Commando is still running just fine.
 
robs ss said:
Well. I've been using Royal Purple HPS 20W50 since Jim's recommendation and am very happy with it.
If "someone" wants to criticise it - bugger 'em! No nerves here.
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Seems to available on eBay.co.uk so may give it a try when I exhaust my stock of XL
 
YING said:
Rob,
I completely agree with you on that.How much more information do we need on this matter?
Mike
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No one is knocking anyone's knowledge, experience or hard work, just indicating what the manufacturer of the product is stating..if this is too much information then so be it
 
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L.A.B. said:
My main point was that as olympus lives in the UK then what's available in the US or elsewhere is irrelevant if it's not available here.
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I guess it's another British verses US English thing. If you went to a auto parts store here and asked for Mineral Oil you would get a blank stare or told to go to a grocery or drug store. Although conventional motor oil starts as crude oil, and mineral oil usually does as well we don't put mineral oil in engines, we mostly put it on skin.

Also, this is a US site about British motorcycles. If we are to tailor our replies to the country of the poster then I suspect that there will be a lot less relies having to study in advance what's available in each country - maybe that's a good thing.
 
Had a response from Castrol

Good morning Malcolm,

Roller bearings should use a monograde oil, as the shear effect of the bearings can cause a multi-grade engine oil to lose its viscosity. However this would occur over a number of miles so if your bikes are not in regular use then you may not have found any ill effects of using 20w/50

Depending on the bike, our XL30 monograde may be the more suitable alternative.

If you can advise on what bikes you’re using, we can investigate to find the manufacturers recommendations.

Best regards,




Brendan Goodjohn

Business Development Executive

Castrol Classic oils
 
marshg246 said:
I guess it's another British verses US English thing.
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No, Castrol USA still calls it mineral oil.
www.castrol.com

Motorcycle Mineral Oils for Smooth Performance | Castrol® USA

Motorcycle mineral oils provide enhanced cooling and protection for older engines. Find the right Motorcycle mineral oils for your bike today!
www.castrol.com www.castrol.com
USA.

Difference between synthetic oil and mineral oil | TotalEnergies

There are two main types of engine oils: mineral oils and synthetic oils. Let’s explore their features and differences!
services.us.totalenergies.com services.us.totalenergies.com
 
Mineral oils are made into multigrade by starting off with the lowest viscosity and then adding viscosity altering additives. So when you make a mineral 20/50W you start with 20 viscosity oil. If the viscosity altering chemicals stop working your 20/50W becomes straight 20.

Fully synthetic oil are multigrade as is if made as a multigrade with no additives to degrade. If anything over time it will thicker slightly.


For example, conventional 5W-30 motor oil is a petroleum-based oil that is thick at low temperatures and thin at high temperatures. To change this variance, oil manufacturers use additives to change the oil's properties, reducing its viscosity at lower temperatures and thickening the oil at higher temperatures. When it's freshly made, conventional 5W-30 motor oil acts like its synthetic counterpart, but over time, the chemical additives break down or vaporize, returning the oil to its original consistency.

By contrast, synthetic oils are designed to match a specific type of multi-grade oil from the beginning. Even without additives, a synthetic 5W-30 motor oil will not degrade or change viscosity—it may only become slightly thicker from contaminants.
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