Royal Purple?

[Mr Gazza]

Thank you for a considered reply Jeff.
We think along very similar lines. I sat in the shed this afternoon and thought I might as well stick with the Castrol Power 1 as I have done for so long. In fact your comment about "Lubricant formerly known as Royal Purple" would be enough to make me boycott it completely.
I too have drained the oil cooler on occasion, but mostly can't be arsed. I do worry about the moments on first start up when the cooler is filling and not passing oil to the mains.

I think given the total lack of any wear problems in my engine, that I will just stick to the same oil.. And you have reinforced that view.

Comstock's tests were probably not relevant to a more modern engine anyway, but they did highlight some good and bad oils to use in Commando engines and for that matter many old twins.

I looked up Morris Golden film and noted that it is for "classic" engines with no filtration system and so is a very low detergent oil. My Commando is newly rebuilt and has a full flow cartridge filter, so I will going for high detergent from the start.

On another subject I have mailed Morris about their EP 80w90 for use in the AMC gearbox. There is a belief that sulphur in EP oils destroy "Yellow metals" which are very common in the AMC, and lots of other old British gearboxes. I bought the oil a long time ago before hearing the Sulphur/EP oil story, so I want to know if I can use it in my expensively restored gearbox... I'll let you know.

Thanks for all the comments.

[Mr Gazza]

Well Ryan, in the technical department of Morris Oils picked up his mail this morning and promptly replied to me.

He confirmed that the EP80w90 does indeed contain Sulphur as part of the extreme pressure additives and kindly recommended that I don't use that in my gearbox.

He put me onto Golden film AG90 which will be safe.

I'm impressed with Ryan and Morris Oils for a prompt and sensible answer.. Well done.

So there's a tip for you to pass onto your classic riding mates Roger. Drain any EP gear oil out of your gearbox immediately and replace with AG90 or non EP oil. I've heard that a lot of folk are using ATF (automatic transmission fluid) in gearboxes with success, probably better than dissolving the bushes?

[uncle duke]

Hi Gary great bit of work you've done there .I have used EP90 gear oils ever since i've had old triumphs (which is a few years !) & touch wood never had a problem with bushes or any gearbox problems , i did read that GL 5 is a no no as it contains more of the sulphur additives & that GL 4 is ok as its only at really high temperatures that problems can occur. I forwarded your piece from Morris oil's to the Commando owner & he straight away bought some AG90 & some for me as well !! so a big thank you for all your hard work & it's really good that Morris oils got back to you so quickly they seem to be the good guys . I use their 20w/50 Golden film as i haven't fitted a cartridge filter to my Tiger so a good 'classic' oil is a must .I hope to see your commando at one of the meets soon in the coming year .

[Mr Gazza]

Nice one Roger I ordered my AG90 this morning.
I'm glad I asked the question because I went and bought what I thought would be the best stuff assuming that GL-5 would be better than 4, 3 or 2.

EP90 was the standard stuff for most bike gearboxes and was recommended by the manufacturers, (as you know). It has only emerged since the "classic era" that the Sulphur eats the yellow metal (brassy metals). When you think about it those still about today could have been marinating in Sulphur for 40-50 years or maybe more, whether in use or not.
Over 40 years in the case of my Norton. I never had any bother whatsoever with any AMC gearbox when I abused Ajay's about thirty years ago, but when I rinsed out the complete 'box off the Norton prior to refurbishment, I got what I thought was a lot of copperslip out of it. My engineer mate, Hutch, said "That will be the bushes!" He kindly replaced all the bushes and did a needle roller conversion on the output shaft, so all should now be good.

[utopia]

Originally Posted by Mr Gazza

Thank you for a considered reply Jeff.

Ah good.
I was a little concerned that my comments might sound a bit flippant.

I actually pondered the whole question of oil selection a lot longer than my edited reply suggests .. but if I'd posted all of my ramblings folks might have started to talk.

[Flip]

This has been an interesting thread for me too as a year ago I bought my new Moto Guzzi V7 and that has quite a 'car like' set up of engine (10w60), gearbox (75w-90) and final drive (75w-140), presumably all safe in their modern applications?

It got interesting as the oil partner for the Piaggio group is Castrol but the recommended 10w60 engine oil is not imported into the UK which means every main dealer is using another make-certainly the local Piaggio dealers near me selling Aprillia, Vespa, Moto Guzzi use Rock Oil, obviously as long as this meets the required standard it is fine but it did rather make me laugh when under the seat it has a label proudly stating 'Lubricated by Castrol'.

After a chat with Opie Oils technical chaps there were two options available for me, Motul and Silkolene with the Motul being the best option as apparently it's make-up is closer to that of Castrol.

This made me wonder how many other main dealers don't use the manufacturers recommended brand of oil as I remember years ago a family run Yamaha dealership (which sadly closed due to the corporate strings being tightened for them to conform to a uniformed showroom like all the other dealerships in the country) use to use Morris lubricants rather than the factory 'Yamalube'.