15W40 4T engine oil -unobtainium?

ChillRider · 12-02-2020, 03:51 AM

Sooo.... an oil thread

Jokes apart, the service manual for my ZongShen Sierra/ZS200-GY2/LZX200-GY2 (depending on your market), despite using a close copy of the Yamaha TW200 engine, recommends just "15W40 SF" oil. That's it. No outside temp ranges, no driving conditions differentiation, no JASO MA/MA2 certification, nothing.

The thing is, that weight of oil is nearly impossible to come by in "motorcycle grade" 4T formulations (with at least a JASO MA endorsement), at least in Greece. The most common commercially available grades seem to be:

10W40 (an OK substitute in colder months, usually semi-synthetic)
20W50 (OK for spring-summer, but struggling on cold starts, and usually oil of that weight is also 100% mineral, so not the best for durability, no matter how thick it is)
15W50 (a good compromise between better cold start performance and top-range protection, and oils of that grade are almost always at least semi-synthetic).
There is also more specialty/expensive stuff like 20W40, 10W50, 5W30 or even 10W60 for enduro racing etc., if someone really needs it, but no 15W40, nope.

The most commonly available oils in a 15W-40 weight seem to be very basic engine mineral oils, often marketed as "Heavy Duty Diesel" or "Fleet/Multipurpose" or even "Agricultural" use, and often only available at quite low API grades, like API SG grades or even lower. API SF/CD grades are not uncommon, and of course no claims of suitability for wet clutch applications. And nope, we don't get Shell Rotella with its fancy JASO MA endorsement here

Can one really pour in such a basic mineral oil in a motorcycle crankcase and expect it to perform? I've heard stories of delivery guys just using the cheapest 20W50 motor oil they can find for their (4-stroke, wet-clutch) underbone motorcycles (Honda Cub, Yamaha Townmate and similar, with a semi-auto transmission), not even caring about whether it's suitable for wet clutch applications, but those motorcycles are obviously designed for that kind of abuse, and their wet clutch is not actuated in the same manner as a fully manual motorcycle.

I guess that such basic/general purpose oils won't have much in the way of specialized friction modifiers/energy conserving additives, exactly in order to be compatible with a broad array of engines (e.g. some "Agricultural" oils claim suitability with wet clutch or even hydraulic applications), but are theyt really safe to use without a JASO MA/MA2 endorsement? Or are those chinabikes built to cope with even the lowest grade of commercially available oil, if necessary?

12-02-2020, 03:51 AM	#1
ChillRider Join Date: Jun 2020 Location: A small country with a funny name Posts: 164	15W40 4T engine oil -unobtainium? Sooo.... an oil thread Jokes apart, the service manual for my ZongShen Sierra/ZS200-GY2/LZX200-GY2 (depending on your market), despite using a close copy of the Yamaha TW200 engine, recommends just "15W40 SF" oil. That's it. No outside temp ranges, no driving conditions differentiation, no JASO MA/MA2 certification, nothing. The thing is, that weight of oil is nearly impossible to come by in "motorcycle grade" 4T formulations (with at least a JASO MA endorsement), at least in Greece. The most common commercially available grades seem to be: 10W40 (an OK substitute in colder months, usually semi-synthetic) 20W50 (OK for spring-summer, but struggling on cold starts, and usually oil of that weight is also 100% mineral, so not the best for durability, no matter how thick it is) 15W50 (a good compromise between better cold start performance and top-range protection, and oils of that grade are almost always at least semi-synthetic). There is also more specialty/expensive stuff like 20W40, 10W50, 5W30 or even 10W60 for enduro racing etc., if someone really needs it, but no 15W40, nope. The most commonly available oils in a 15W-40 weight seem to be very basic engine mineral oils, often marketed as "Heavy Duty Diesel" or "Fleet/Multipurpose" or even "Agricultural" use, and often only available at quite low API grades, like API SG grades or even lower. API SF/CD grades are not uncommon, and of course no claims of suitability for wet clutch applications. And nope, we don't get Shell Rotella with its fancy JASO MA endorsement here Can one really pour in such a basic mineral oil in a motorcycle crankcase and expect it to perform? I've heard stories of delivery guys just using the cheapest 20W50 motor oil they can find for their (4-stroke, wet-clutch) underbone motorcycles (Honda Cub, Yamaha Townmate and similar, with a semi-auto transmission), not even caring about whether it's suitable for wet clutch applications, but those motorcycles are obviously designed for that kind of abuse, and their wet clutch is not actuated in the same manner as a fully manual motorcycle. I guess that such basic/general purpose oils won't have much in the way of specialized friction modifiers/energy conserving additives, exactly in order to be compatible with a broad array of engines (e.g. some "Agricultural" oils claim suitability with wet clutch or even hydraulic applications), but are theyt really safe to use without a JASO MA/MA2 endorsement? Or are those chinabikes built to cope with even the lowest grade of commercially available oil, if necessary?
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