10W40 after 10W50?

Hi!
I have to do the 24kms service. The previous owner used 10W50 engine oil, but the OEM is 10W40. Im hesitating wether change back to 10W40 or keep the 10W50 line... I have to change the oil filter also, so if I seep down the oil, change the oil filter, I can fill up the system with 10W40? Isnt that a problem?

Thanks!

You can run anything you like. No problem switching between brands or weights. It's a Honda, it will run on anything.
Just make sure you don't run a oil with energy conserving in the API service ring and you will be fine.

OEM is 10W30

10W50 should not be used in NC.

A 10W50 is intended for mostly air-cooled engines like the older BMW boxers. The NC doesn't need it, having water cooling and modern tight tolerances, but it won't hurt anything but the fuel economy.

As has been said, just put in a good motorcycle 10w30 or 10w40. Mixing is not a problem at all. Personally, I run 10w40 due to the summer heat in TX. Plus, it is a much more common viscosity to find motorcycle oil in than the 10w30, which is usually more of an automotive spec. It can be done, but you might have to look around a little more.

10w30 or 10w40 is specified in the service manual. Finding a JASO MA 10w30 locally is next to impossible, and even dealerships use bulk 10w40 for all their bikes. A favorite of many people is Shell Rotella, either the 15w40 or 5w40 synthetic that meets JASO MA and is readily available and a great price.

The answer to the original question is, yes, you can change from 10w50 to 10w40.

If we start recommending other oil weights and specific brands, then this will become another oil thread, and nobody wants that, right?

670cc said:

The answer to the original question is, yes, you can change from 10w50 to 10w40.

If we start recommending other oil weights and specific brands, then this will become another oil thread, and nobody wants that, right?

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Agree, but also think all agree that 10W50 is not a good oil choice for liquid cooled tight tolerance NC engine.

Fuzzy said:

Agree, but also think all agree that 10W50 is not a good oil choice for liquid cooled tight tolerance NC engine.

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meh - I live in HOT HOT HOT traffic rich Tampa Bay and use 20-50 semi-synthetic motorcycle oil on this slow spinning stroker engine. Heat protection.

I seem to remember a similar topic on a Nissan Altima forum a while back. Nissan recommends an extremely light weight oil in their 4 cylinder engines and at the time it was hard to find and, if you could find some it was expensive. That thread had very similar responses to this one until one member decided to ask Nissan Customer Service. Their reply was that the new engine was designed for the light weight oil and the engine's oil journals were sized for it. They said that higher than recommended oil viscosity could result in restricted flow through the small journals and possibly decrease the oil circulation to the point where overheating or damage could occur.
I don't know if Honda used the same approach on the NC engine or they just recommend the light weight oil for fuel economy, but just in case I think I'll use the viscosity that Honda recommends for the NC.

Bob

Honda reccomends 10-30 across the board. Nothing to do with engine design.

bigjeff said:

meh - I live in HOT HOT HOT traffic rich Tampa Bay and use 20-50 semi-synthetic motorcycle oil on this slow spinning stroker engine. Heat protection.

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It doesn't matter where you live......the engine is liquid cooled and operates in a narrow band of operating temperature. Use what you want but using an oil outside of Honda's specification is probably protecting it less than using a recommended viscosity.

Smallville said:

Honda reccomends 10-30 across the board. Nothing to do with engine design.

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Honda don't live in Florida.

670cc said:

The answer to the original question is, yes, you can change from 10w50 to 10w40.

If we start recommending other oil weights and specific brands, then this will become another oil thread, and nobody wants that, right?

Click to expand...

You were right. Another oil thread and you did properly answer the actual question.