OK guys, what's the best motorcycle synthetic?

[tmcafe]

Originally Posted By: Redline955
Oil threads are a source of arguments and misinformation on the M/C sites I frequent. It can get pretty amusing. I agree with Drew. You could use just about any quality oil if you change it at 3 to 5,000 miles.
"Just about any quality oil"--yes, but what does it mean exactly? Some of the OEMs say (or used to say) "SG or higher". But that may not be the case anymore. I have no problem using any oil from Walmart if it does the job of protecting the high-stress/wear prone parts and stay in grade. But when one of the best tech guys say that they've seen a lot of worn (flat tappet) cams on Moto Guzzis recently, and they suspect the new oil formulations (not SG anymore), I'm becoming suspicious too. And they're not trying to sell us Guzzi owners oil, and they keep their own bikes running on high-end oil. As far as temperature goes, I've seen pretty often 130º C in the summer. At that level, the oil better not shear out of grade. For me the question is still open. Right now my Guzzi has Mobile 1 Racing 10W-40, but with sunruh's UOAs (he said both Mobil and Amsoil sheared out of grade pretty fast), I'm not sure I want to take risks. If a cheapo Diesel oil works as well or better than the $$ motorcycle oils, I'll go that way just fine. But if the $$ oil is giving better protection of essential components, why gamble?

 

[Drew2000]

Originally Posted By: tmcafe
Originally Posted By: Redline955
Oil threads are a source of arguments and misinformation on the M/C sites I frequent. It can get pretty amusing. I agree with Drew. You could use just about any quality oil if you change it at 3 to 5,000 miles.
"Just about any quality oil"--yes, but what does it mean exactly? Some of the OEMs say (or used to say) "SG or higher". But that may not be the case anymore. I have no problem using any oil from Walmart if it does the job of protecting the high-stress/wear prone parts and stay in grade. But when one of the best tech guys say that they've seen a lot of worn (flat tappet) cams on Moto Guzzis recently, and they suspect the new oil formulations (not SG anymore), I'm becoming suspicious too. And they're not trying to sell us Guzzi owners oil, and they keep their own bikes running on high-end oil. As far as temperature goes, I've seen pretty often 130º C in the summer. At that level, the oil better not shear out of grade. For me the question is still open. Right now my Guzzi has Mobile 1 Racing 10W-40, but with sunruh's UOAs (he said both Mobil and Amsoil sheared out of grade pretty fast), I'm not sure I want to take risks. If a cheapo Diesel oil works as well or better than the $$ motorcycle oils, I'll go that way just fine. But if the $$ oil is giving better protection of essential components, why gamble?


Notice I qualified the statement "liquid-cooled" and "Japanese of German"

Air cooled bikes like the MG's can be brutal on oil.

 

[tmcafe]

Originally Posted By: Drew2000
Notice I qualified the statement "liquid-cooled" and "Japanese of German"

Air cooled bikes like the MG's can be brutal on oil.
Yup, I noticed.

I'm also wondering (probably it's a no-brainer) if different engines do different things to engine oil. In other words, shearing is perhaps more of a big deal with wet clutches where engine oil is shared by the tranny. OTOH like in the case of air-cooled bikes, temperature is a bigger deal. And then particular items, like the flat tappet cams and other high-pressure, high-stress areas, etc. So perhaps a UOA should apply more to the particular type of bike the oil was used in. I'm wondering if there's a fast way of doing UOAs (in other words, not waiting for the scheduled 3k OCI, but rather (ab)using the engine in a thougher 500 mile run at higher revs, then comparing with another oil used in a similar way in the same bike.

BTW, what's the shelf life of a motor oil that was used for some 500-1000 miles? (I'm talking about the effects of the combustion by-products, oxidation, etc)

 

[Drew2000]

I think the quality of the cam-shaft steel goes a long way in how much wear occurs on the cam. Maybe some mfgs. use a harder steel that wears better. My fairly hard-ridden bikes (Honda & Yamaha) use shim-under-bucket and show no cam wear pushing 25k miles each.That's why I like to use a high-zinc oil like the older formula of Rotella or Rotella Syn. The tranny gears of a shared sump is what chews up the oil before the engine does.

If you wanted to sample the oil in between changes, you might be able to suck it out with some thin, clean tubing from the oil filler. I would just ride the bike as you normally do and sample at (or just before) oil change time and make your decisions then. I don't think there will be -that- much wear at 3k intervals, and if you plan to keep the bike a long time, you can tweak your oil findings until you find one that works best. In your air-cooled MG, a cheaper 15w40 diesel oil might work well till 3k, but a more expensive syn might get you to 5k or more.

Since you live in Boise, and have a pretty long riding season, the conditions between desert-like summer heat and the cooler spring and fall will make a big difference on oil life, esp. air cooled engines. I really wouldn't keep used oil for re-use more than a few months, even if it has only 500-1000 miles on it.

 

[KernelK]

At the time that I owned my Sport 1100i, the factory recommended oil was Mobil 1 15w-50. The big thing with these big air cooled twins is to keep them in motion, not sitting idling and certainly not revving at a stand still. The big two valve motors probably put a little over 80, maybe 85 hp to the road at most. Run sensibly and maintained, these old tractor motors will deliver many pleasurable miles. Few motors sound as good as a big two valve Guzzi with a set of pipes at full chat.

Regarding the shelf life of a 500-1000 mile oil, provided that it is a premium and/or synthetic oil, I see no reason the machine cannot be parked over the winter and put into service the following year. High grade and synthetic oils are designed with additive concentrations for this very purpose.

 

[tmcafe]

Originally Posted By: Drew2000
I think the quality of the cam-shaft steel goes a long way in how much wear occurs on the cam. Maybe some mfgs. use a harder steel that wears better. My fairly hard-ridden bikes (Honda & Yamaha) use shim-under-bucket and show no cam wear pushing 25k miles each.That's why I like to use a high-zinc oil like the older formula of Rotella or Rotella Syn. The tranny gears of a shared sump is what chews up the oil before the engine does.

If you wanted to sample the oil in between changes, you might be able to suck it out with some thin, clean tubing from the oil filler. I would just ride the bike as you normally do and sample at (or just before) oil change time and make your decisions then. I don't think there will be -that- much wear at 3k intervals, and if you plan to keep the bike a long time, you can tweak your oil findings until you find one that works best. In your air-cooled MG, a cheaper 15w40 diesel oil might work well till 3k, but a more expensive syn might get you to 5k or more.

Since you live in Boise, and have a pretty long riding season, the conditions between desert-like summer heat and the cooler spring and fall will make a big difference on oil life, esp. air cooled engines. I really wouldn't keep used oil for re-use more than a few months, even if it has only 500-1000 miles on it.
Thanks for the comments. I remember reading a story from a hot rod engine building website where the writer was discussing cam issues, what to avoid and how to prevent fast wear (good oil). Re: Rotella, you're talking about CI vs. CJ formulations (the latter having less Zn?) Changing the oil at 3k isn't a problem, it's a breeze on the Guzzi (unlike the F650GS dry sump). If I had to choose, I'd pick a good synthetic (yet which ?, as there appears to be a lot of mixed results

) that could go to the recommended OEM 6k change interval. And yes, there are big differences here between days with 100F and those below freezing, when it's still okay to ride if there's no ice or snow on the road, which is common here.

 

[tmcafe]

Originally Posted By: KernelK

At the time that I owned my Sport 1100i, the factory recommended oil was Mobil 1 15w-50. The big thing with these big air cooled twins is to keep them in motion, not sitting idling and certainly not revving at a stand still. The big two valve motors probably put a little over 80, maybe 85 hp to the road at most. Run sensibly and maintained, these old tractor motors will deliver many pleasurable miles. Few motors sound as good as a big two valve Guzzi with a set of pipes at full chat.

Regarding the shelf life of a 500-1000 mile oil, provided that it is a premium and/or synthetic oil, I see no reason the machine cannot be parked over the winter and put into service the following year. High grade and synthetic oils are designed with additive concentrations for this very purpose.
Yup, Guzzis tractors rock!

and there are plenty that have racked up lots of miles. That's why I want to take good care of mine, including lube.