auto oil vs motorcycle oil

[CS1983]

Have some extra bottles of oil from truck I just sold which is the same basic stuff as for the bike: 10w-40

Internet seems conflicted on if auto oil =/= motorcycle oil. Some things I've found say dedicated motorcycle oil is needed and others say that claim is snake oil and one can use regular engine oil in a bike.

eta: I should clarify this is a wet clutch bike in case that changes answers due to friction issues and slipping.

Any thoughts?

[Great-Kazoo]

Shouldn't be an issue with the proper viscosity.
http://www.ducatimeccanica.com/oil.html

http://www.wisegeek.org/can-i-put-oi...motorcycle.htm

[TAR31]

If the oil has friction modifier, which most car oils do, it can cause clutch slippage. Diesel engine oils don't and can be used in motorcycles. I personally used Rotella 15/40 in all my wet clutch engines.

[fly boy]

look on the back of the bottle for a little circle thing. You DO NOT want something that's energy something. I'm not at home right meow so I can't take a picture.

I ran mobil 1 synthetic 15w40 in my CBR, and Rotella synthetic in my V-twin engines.

heres a quick things I found....

[jmg8550]

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.

[68Charger]

over at bobistheoilguy.com the discussion was that car engine oils could be an issue because of friction modifiers... but what they call HDEO (Heavy Duty Engine Oil) that is intended for Diesels, which sometimes also have wet clutches and gear boxes will be 100% compatible with motorcycle applications.

I've always run Rotella T 5w-40 synthetic in my Honda Shadow Sabre 1100.. and it now has 65,000 miles

[SouthPaw]

look on the back of the bottle for a little circle thing. You DO NOT want something that's energy something. I'm not at home right meow so I can't take a picture.

I ran mobil 1 synthetic 15w40 in my CBR, and Rotella synthetic in my V-twin engines.

heres a quick things I found....

I was always told by shops and my small time mechanic to stay away from energy savings oil because it causes clutch issues. I have always, ALWAYS ran Rotella 5W-40 synthetic in my motorcycles (9 bikes and counting). Not one showed any signs of damage, problems, or clutch issues even turning the engine at 15K RPM. Actually some of my bikes it smoothed out shifting and finding neutral. If you google Rotella 5W-40 motorcycle, you will see thousands of people using it and the poeple they aren't using it are asking why they shouldn't. I have yet to find anyone that has said it has caused damage to their bike.

This is an email from Shell that someone asked awhile back about Rotella 5W-40 being wet clutch rated (JASO-MA)

Here is the email from a Rotella engineer that I found on the Shell forums.

"We recently ran the JASO MA friction test on Rotella T with Triple Protection 15W-40, Rotella T Synthetic 5W-40 (CI-4) and our soon to be introduced (within the next 2 months) Rotella T Synthetic 5W-40 CJ-4.

All three oils passed the wet clutch friction test. Rotella T Synthetic 5W-40 (CI-4) has more than 1.2% ash (JASO MA spec limit) so it can not be classified as JASO MA. However, Rotella T with Triple Protection 15W-40 and our soon to be introduced Rotella T Synthetic 5W-40 CJ-4 do meet JASO MA."

If you have any additional questions please call us at 800-231-6950.
Thank you for your interest in Shell products."

Richard Moore
Staff Engineer
Shell Global Solutions (US) Inc.

[Great-Kazoo]

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.

B&G EPC was my go to additive as well as other B&G products

[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?