Follower scar oil tests (2018)

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Royal Purple for the UK types just a sample there are others
 
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Fast Eddie said:
Jim, what do I not understand about your table?

The Bel Ray out performed the Royal Purple with regards to load, is how I read it...

And Mobil 1 v twin is WAY down the list, it only climbed up close to the top when combined with 8.5% BGMOA...
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For maximum load the Bel Ray is the highest -but when you add the high friction it does not do as well.

Heat from friction is something that is important because high friction creates more heat and more heat drops the load capacity.

These tests were done with controlled temperature, controlled temperature is not something that is possible with an air cooled motor, so this is an important consideration.

And yes, Mobil 1 is well down on the list of load capacity, but the load capacity has proven to be high enough for most stock operation and it is very resistant to oxidation from heat.

So the way the list of oil is sorted, the highest load capacity is at the top of the list. But the list was not made with the idea that the best oil is at the top. Sometimes the best choice is going to be determined by climate, how the bike is used and even price and availability.

I can make a list of the top choices for my use and location -but then it's not likely to be right for someone else.

Royal Purple does the best job of meeting my requirements.
1. The load capacity is more than adequate
2. It generates very little heat from friction
3. It oxidizes very slowly which means I can do a 4000 mile trip without a change.

4. In testing I did that is not represented in the chart, I did some testing with a reduced load but I shut down the cooling system and let the temperature continue to rise until failure. The Royal Purple won that test -but that test may only be important to a few guys in the desert SW or a couple people in Australia that tend to run long days at high speed on hot days.
Most people will never see oil temps up there over 350 degrees.
 
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Thanks Jim.

And good spot on the RP availability Onder and Cab.

Looks like I gotta buy Royal Purple now then...!
 
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Fast Eddie said:
Thanks Jim.

And good spot on the RP availability Onder and Cab.

Looks like I gotta buy Royal Purple now then...!
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Just ordered some here FE - $102 including shipping - probably about 25GBP!! (or USD)

Thanks muchly Jim!!
 
robs ss said:
Just ordered some here FE - $102 including shipping - probably about 25GBP!! (or USD)

Thanks muchly Jim!!
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It seems to change here, last time I bought a ‘batch’ I could not find RP in the U.K. and buying from the US was extortionate shipping costs to U.K.

But this time it, Rival motorsport had plenty in stock, and free postage!

So it looks like I’m now a Royal Purpler...
 
Had this headache a while ago and I think I bought the wrong RP 20-50w but I recall the 961 needs 10-50w ??

I live in AUS its ALLWAYS HOT man !!
 
Given the truly fantastic work that Jim did on this topic... and the high level of interest in it... and the ‘myth busting’ that Jim did... and the potential cost of using the wrong oil...

Why don’t Andover step up and start stocking Royal Purple? They don’t need to stock all the weird and wonderful variants, just gallons of HPS 20w50 fully synthetic. Simples.

How about it Madnorton? You worried it’ll reduce sales of internal engine parts ?!?;)
 
As Jim said, not all of us have to deal with heat. The other thing to think about is oil change interval. A modern bike has modern filtering. Older bikes rarely have any or if they do it is for debris that is larger than a golf ball.
So dumping the oil every thousand miles removes a lot of floating tiny gritnoids. That is a technical term of course.
You really dont want to be dumping RP every thousand miles.
Don't you just love oil threads? :-0
 
It is down to Jims work that I changed from using Morris V twin 20/50 to Castrol XL 20/50. As I have a lot of bikes the most mileage each of my four Norton twins are likely to do in a year is about 1500. The Castrol makes sense as I can afford to change it every year. If I lived somewhere with hot weather my choice might be different.
 
Heat isn’t just inflicted by desert sunshine though boys...

An engine initially designed as a 7:1cr 500cc that’s been abusively punched out to 920cc with 11:1cr is gonna make more heat than the fin designers initially calculated !

And bikes used on the track, even ‘just’ none competitive track days, do get a hard time. One can often be kept waiting in ‘warm up’ areas longer than intended, then follow it up with 20 mins or so of almost constant at, or close to, the red line... that’s gonna give any oil a hard time.

Thus, to me at least, a gallon of RP once or twice a year is really a drop in the ocean financially speaking :rolleyes: and anyway, it makes me feel good about it !
 
Same as the two above , for my roadgoing Cdo (s) and Atlas Castrol XL 20w50 and for the big toys Bel Ray , however they are both difficult to come by in Frog land , bel ray came from Spain and XL from Germany , and if I want Royal Purple the shipping cost from the MARS planet will cost me my meagre pension..........
 
Fast Eddie said:
Trouble is, the 961 ain’t one o’ them!

Comnoz was of course testing oils for the ‘old’ Commando. One really interesting thing he discovered is that old engines place very different demands on oils.

Yes, your 961 might be a new bike, but it’s a seriously old skool engine!

‘Modern’ engines are designed differently, so need a suitable oil.

‘Old’ engines do not manage heat so well, so can ‘cook’ oils. Tolerances tends to be much bigger, so need oils able to handle this. The Harley gearbox is a famously clunky affair, and specialist oils have been designed specifically for this.

Personally, I still intend to use the Bel-Ray gear oil as it was specifically designed for this box.

And I’m thinking the the Bel-Ray 10w 50 would be good in the 961 engine. It had one of the highest load ratings in Comnoz’ tests, being a 10w it should be the same when cold as a 10w 40. But being a 10w 50 should add an extra element of protection on not days, track days, etc.

However, having said all of that, it’s very easy to over worry this topic!

Regular oil changes are probably more important that oil choice.

But... I wouldn’t let the fact that an oil, any oil, is free affect my decision IMHO...
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OK, so I use Royal Purple in my Commando and Castrol classic 20-50 in the Atlas. For my sins I also have a 1979 Yamaha XS750. This has a wet clutch running in the engine oil, not sure if engine classed as 'old' or 'new' so which oil best for bikes with integral gearboxes and clutch?
 
The Bel Ray 10w50 v twin synthetic is suitable for wet clutches.

If I recall correctly, the Royal Purple is not.
 
marinatlas said:
Same as the two above , for my roadgoing Cdo (s) and Atlas Castrol XL 20w50 and for the big toys Bel Ray , however they are both difficult to come by in Frog land , bel ray came from Spain and XL from Germany , and if I want Royal Purple the shipping cost from the MARS planet will cost me my meagre pension..........
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Pierre, where is your source in Spain for Bel-Ray?
 
Fast Eddie said:
The Bel Ray 10w50 v twin synthetic is suitable for wet clutches.

If I recall correctly, the Royal Purple is not.
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If Royal Purple is easy to come by, they do make a motorcycle oil also that is suitable for wet clutches. it was not quite as low a friction as the HPR but it was lower than the Bel Ray.
 
comnoz said:
If Royal Purple is easy to come by, they do make a motorcycle oil also that is suitable for wet clutches. it was not quite as low a friction as the HPR but it was lower than the Bel Ray.
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Can you recall what its called Jim?

It’s important to be precise about these things because, as your testing showed, sometimes oils that appeared very similar initially, and were even from the same maker, tested VERY differently!
 
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