Difference in oil weights

[OutofOrder]

Took my motorcycle into the dealership for an oil change. Manual calls for 10w40 but the dealership put in 10w30. Should I worry about this at all? Also, I plan on a switching to a heavy duty oil on my next change. Since I can't find a 10w40 heavy duty oil, I would going to use Rotella 15w40. Is the 5 weigh difference anything to be concerned with?

 

[ldsmss]

if your bike is air cooled, don't use rotella. aircooled motors operate at a higher temp. than liq. cooled. you cannot go wronge using manufactures product. ldsmss.

 

[MJ Synthetics]

Took my motorcycle into the dealership for an oil change. Manual calls for 10w40 but the dealership put in 10w30. Should I worry about this at all? Also, I plan on a switching to a heavy duty oil on my next change. Since I can't find a 10w40 heavy duty oil, I would going to use Rotella 15w40. Is the 5 weigh difference anything to be concerned with?

Please remember that if the MFG calls for a XXW-40 oil that you should be using that weight in an application such as a dirt bike. Not knowing what kind of bike (street or dirt)and conditions you ride in (Climate, Dirt, High elevations etc) its hard for me to pin down anything with real substanence.

Just so you know the MCF Amsoil 10W-40 is specially formulated for wet clutch applications and the high temps and revs we put on out dirt bikes. It also carries a viscosity of a 60 weight oil. Its 100% full synthetic and I race what I sell. My son races KTM 200's I race a YZ450F that is the oil we use in both bikes. Both of us have won multiple class championships in the last 3 year running this oil. My son also uses the Dominator 2 stroke oil with great success.

Now I sound like a commercial ..................sorry. Bikes are my passion and racing them 30-40 weekends a year you get to know what works and what doesn't.

So I can't question the decision by the dealer to put 10W-30 in it without a little more information.

 

[OutofOrder]

Guess I was a bit vague in my post. I have a 1984 Honda magna 750 liquid cooled that got the 10w30. I also have a 1980 Kawasaki kz1000 air cooled that currently runs 20w50 castrol motorcycle oil, but it's so expensive Im thinking of switching that to 15w40 rotella as well. Neither manual says anything about motorccle specific oil. Did that stuff even exist in the early 80s?

 

[MJ Synthetics]

Guess I was a bit vague in my post. I have a 1984 Honda magna 750 liquid cooled that got the 10w30. I also have a 1980 Kawasaki kz1000 air cooled that currently runs 20w50 castrol motorcycle oil, but it's so expensive Im thinking of switching that to 15w40 rotella as well. Neither manual says anything about motorccle specific oil. Did that stuff even exist in the early 80s?

Yes actually it started in 1972.

Well I think I would be using 20W-50 in both bikes. If your interested all my street guys buy the Amsoil MCV 20W-50. I can probabally save you some money over the Castrol unless of course you get it out the back door or some crazy deal like that. How much are you paying for the Castrol if you don't mind me asking? I would caution you in using Rotella. It doesn't have some of the additives that are put into a motorcycle specific oil such as additives for wet clutch applications.

If you care to do a little reading here is a great study of Motorcycle Oils.

Now I ask you to keep an open mind because Amsoil paid for the study Castrol sure wasn't going too. Please don't skim through it. You will miss critical information on each test and not know if a high result or low is good for that test in the results.

The study was performed by an independent lab using ASTM test standards. It will also show that Amsoil is not the best performer in all catagories however it is always the best in the 4 ball wear test. I think that is a critical test for us the consumer to pay attention too. It will show that over all Amsoil was the best all around oil in the study.

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Dane