auto oil vs motorcycle oil

[TFOGGER]

Also wondering if motorcycles need oil with zinc to help protect the bearings. Modern oils don't have the zinc additives, and older engines need it or the bearings will be destroyed.

The zinc is needed to prevent gear teeth from galling in bikes that use a shared oil supply between engine and transmission (most modern bikes). Diesel oils work well in most applications, but have reduced shear resistance at very high rpm compared to engineered motorcycle specific oils, leading to more rapid viscosity loss at elevated rpm (over 10000 or so).

[CS1983]

The zinc is needed to prevent gear teeth from galling in bikes that use a shared oil supply between engine and transmission (most modern bikes). Diesel oils work well in most applications, but have reduced shear resistance at very high rpm compared to engineered motorcycle specific oils, leading to more rapid viscosity loss at elevated rpm (over 10000 or so).

For something like a TW200 or XT350, would you recommend just sticking with motorcycle specific oils?

[Martinjmpr]

For something like a TW200 or XT350, would you recommend just sticking with motorcycle specific oils?

There are probably as many opinions on this as there are people on the internet. I've seen "which oil" discussions turn nasty for some bizarre reason.

Certainly a motorcycle-specific oil would be the safest way to go. I'm a bit of a cheap SOB so I run non-energy-conserving 10w40 in my wet clutch bike (Triumph Bonneville) and in my dry-clutch BMW I can run anything I want, even energy conserving, since it has a separate gear box it doesn't matter.

[TFOGGER]

For something like a TW200 or XT350, would you recommend just sticking with motorcycle specific oils?

Since they both use a little over a quart of oil each, the cost savings using diesel oil is not very great, so motorcycle specific oil is probably a good choice. Neither one is likely to particularly stress the the oil's lubrication capabilities, so pretty much any oil rated API SE-to API SH would probably work.
Ask any 4 guys about opinions on oil, and you'll get 5 answers. I believe engineers know what they're designing the oil to do, and buy my oil accordingly.

[CS1983]

Since they both use a little over a quart of oil each, the cost savings using diesel oil is not very great, so motorcycle specific oil is probably a good choice. Neither one is likely to particularly stress the the oil's lubrication capabilities, so pretty much any oil rated API SE-to API SH would probably work.
Ask any 4 guys about opinions on oil, and you'll get 5 answers. I believe engineers know what they're designing the oil to do, and buy my oil accordingly.

Thank you, sir.