My Moto Guzzi Stone requires a 20w-50 oil with an SG rating. These are pretty hard to find. I'm using Halvoline which the container says is a SJ rating but the website states is a SJ AND SG rating. Can I assume that any SJ rating is also an SG rating? What does this SG rating mean anyway? Is it a measure of the oil's detergency?
SG Rating
- Thread starter Mackers
- Start date
- Status
That oil came out in model year 1993, and older engines.
SG is an obsolete API rating for gas engines. These ratings denote the minimum performance parameters an oil must meet in order to be certified by the API.
Since SG oils are no longer made, you will have to use an oil with the current rating, which is SM. Some SL oils are still being made, too, especially in the heavier grades like 20w50 and 15w40.
Since SG oils are no longer made, you will have to use an oil with the current rating, which is SM. Some SL oils are still being made, too, especially in the heavier grades like 20w50 and 15w40.
If you really want to be careful, get a motorcycle oil with one of the current MC oil ratings.
Official SG oil isn't made anymore. Some boutique oil companies make oil that they claim is SG.
To add to the confusion, there is no reason to not expect SM oil to pass SG test requirements if the equipment to run SG tests is still available.
The two potential problems with an automotive SJ, SM or SL oil are that it might have enough friction reducers to cause problems with a wet clutch. It might also be low enough on additives to protect flat tappet cams that you get into wear problems.
I would recommend checking the Guzzi forums so see what their experiance has been.
Official SG oil isn't made anymore. Some boutique oil companies make oil that they claim is SG.
To add to the confusion, there is no reason to not expect SM oil to pass SG test requirements if the equipment to run SG tests is still available.
The two potential problems with an automotive SJ, SM or SL oil are that it might have enough friction reducers to cause problems with a wet clutch. It might also be low enough on additives to protect flat tappet cams that you get into wear problems.
I would recommend checking the Guzzi forums so see what their experiance has been.
I don't have a Guzzi anymore but if I did, I would run the Havoline Premium 20/50. The gearbox runs separately and the clutch runs dry so an expensive synthetic is not required in the motor in my opinion.
I found that it also paid to periodically lube the splines on the driveshaft with antiseize (copper based) and the rear cush drive splines with a moly grease.
I found that it also paid to periodically lube the splines on the driveshaft with antiseize (copper based) and the rear cush drive splines with a moly grease.
Thanks everyone for your replies. I agree that an expensive synthetic isn't required. But I understand that after the SH rating, levels of zinc and potassium (I think) were reduced to protect catalytic converters. These are necessary on many bikes to reduce wear on camshafts. Can an oil really be both SG and SJ?
On certain Guzzi forums oil threads are an invitation for abuse. From the couple I visit, one of the answers you'd receive, tongue in cheek, would probably be to use yak fat. They seem to run, and survive on anything. Latest blurbs from the factory seem to stress using the recommended viscosity. Is your Stone one with hydraulic lifters? If so I'd recommend doing some research on issues involved with that engine. My 98 Guzzi has had a steady diet of regular Mobil 1 for the last 70,000 miles, while a fellow I'm acquainted with has used nothing but regular Castrol 20-50 for 150,000 miles or so.
Maybe adding something like some SLOB would suffice? Since you don't have wet clutch issues to deal with...
And on a bike "a little goes a long way"?
Sure: an oil can meet both SG & SJ specs. I would opine that a good SL or SM oil would meet or exceed SG or SJ specs, since that is what backward compatibility is all about.
Cheers!
And on a bike "a little goes a long way"?
Sure: an oil can meet both SG & SJ specs. I would opine that a good SL or SM oil would meet or exceed SG or SJ specs, since that is what backward compatibility is all about.
Cheers!
- Status