5w40 vs 10w30 in CBR

[V1]

Last year, I tried Rotella T6 (5w-40) for the first time in my 2012 CBR. The manual calls for 10w-30. However, the 2008-2011 models use 10w-40 with the identical engine as the 2012 and beyond. I felt it was ok to try out the heavier oil.

My initial reaction was that gear shifting was incredibly smooth. Engine vibration might have been reduced slightly. The only negatives were loss of about around 4-5 mpg, and the clutch feels less grippy.

My plan is to drain the T6 at 2000 miles for a UOA, unless somebody convinces me to do it later (or sooner). Up until now, I have used GN4, and changed every 2-3k. All my UOA's show good wear numbers, but the oil thinning to a 20-weight if I remember correctly. I will get around to sharing that data soon.

 

[maverickfhs]

Subscribed for UOA.

BTW, do you ride it hard or not really?

Please update the thread if end up doing a UOA, with mileage and all.

 

[V1]

Sounds good. Will be glad to share. I've done a UOA every change since new. Don't ask my why, because I could not tell you. I just did it. 18k total miles so far.

Riding style runs the gamut. Usually pretty gentle, but plenty of hard pulls on the highway. Couple of track days in the past including one on the current fill. Couple of road trips with high-revving stuff all day. The UOA history has a good mixture.

 

[Dyusik]

I dump my oil according to shift notch predominance. With T6 it came sooner than later. I'm sticking to warm weather stuff (15w and up)

 

[CT8]

4 to 5 MPGs Yikes.

 

[rubberchicken]

I use Amsoil 20w50 in my GTS1000 . Sometimes I use Amsoil 10w40. I too notice a slight reduction in mpg between the 10w40 and 20w50. I was surprised your CBR called for 10w30 as I thought they usually went with 10w40, but my bike is much older than yours.

 

[FZ1]

Smoother shifting in my FZ1 with Amsoil 20-50 vs. Mobil 10-40.FWIW

 

[vronline]

Why not use a motorcycle oil and change as the manual suggests? Probably cheaper than doing all those UOAs too..

 

[V1]

It would be much cheaper, I agree. Honda recommends 10w-30 with 8000 mile intervals. Probably no issue even under moderate engine loading. Curiosity though, what can I say?

 

[SuperSalad]

It sounds to me like your clutch is slipping with that much of a mpg decrease and your description of the clutch gripping less. Personally I'd rather have a grabbier clutch and adjust my usage of the lever than use an oil that causes slip.

 

[ARCOgraphite]

If you do a UOA do you open the filter and wash the metal out of the pleats and weigh it?

The wear materials are in the filter proper not in the UOA report.

Just a suggestion.

 

[V1]

Nope. Never went to that length. Visible metal flakes in the oil filter would suggest big problems to me. Not sure I've ever heard of anybody weighing filter debris. What information would you even get from that?

 

[kschachn]

Originally Posted By: V1
Nope. Never went to that length. Visible metal flakes in the oil filter would suggest big problems to me. Not sure I've ever heard of anybody weighing filter debris. What information would you even get from that?


When I did oil analysis in college for our fluid power department we did that all the time. You both weighed the debris and did an acid digestion with subsequent atomic absorption analysis. Mostly it was looking for a total metals load in the oil, looking for pieces that were too large to otherwise show up on AA. AA has a much lower bound on particle size than does modern ICP but you still won't see "pieces" of metals. That's why a catastrophic failure often times won't be apparent from a standard oil analysis.

 

[V1]

How much oil filter debris could somebody possibly expect to find from a motorcycle engine? And what would that even tell you? Not to squash your point here, but how is this a practical experiment? I've heard of people cutting open filters to see if the filter element was still intact, or to check for visible debris. Just out of curiosity. Don't see how gathering debris and weighing works though.. And, would a UOA not detect trouble if that's what you suspect?

 

[kschachn]

You should find very little if any at all. It depends on the operating conditions and the condition of the engine but in general there should be very little in any ICE filter.

I'm not advocating it be done but it could be if needed. In general a UOA is of very limited usefulness, it shows the continued serviceability of an oil (TBN, TAN) and presence of water/coolant or fuel, but beyond that not a whole lot. An engine can be on the verge of catastrophic disintegration or completely sludged up and yet return acceptable UOA results. For example, if chunks are coming off of bearings and other components those would be too large to appear on an ICP analysis yet the pieces would be trapped in the filter. We saw that once in a while for hydraulic equipment.

Besides TBN/TAN and the other things mentioned above, unless you are testing for the continued serviceability of the oil a UOA is typically a waste of money for most people.

Originally Posted By: V1
How much oil filter debris could somebody possibly expect to find from a motorcycle engine? And what would that even tell you? Not to squash your point here, but how is this a practical experiment? I've heard of people cutting open filters to see if the filter element was still intact, or to check for visible debris. Just out of curiosity. Don't see how gathering debris and weighing works though.. And, would a UOA not detect trouble if that's what you suspect?

 

[FZ1]

Best to use a MC specific oil. The auto oils can be too slippery for your clutch.

 

[sunruh]

O M G
idiots abound ... and posting

and OP...5w40 while a great oil in that blue jug...chews down quickly in a shared sump
depending on your riding rpm range...it might make 1000mi before its 30wt...might
if you like to zing it and row the left foot then maybe not

if you have done a lot...sounds like its time for new clutch plates regardless of what oil you use.

 

[maverickfhs]

BTW, among all of you long time members. Can anyone share a UOA for Rotella 15W-40 or any diesel oil being 5W-40 or 15W-40?

If you have any other link for a 10W-40, not motorcycle specific that would be great too? Thanks a lot.

 

[ammolab]

The oil analysis on my BMW M Coupe showed 6 times the normal lead and copper from "unit average"...rod bearings were bad and a replacement of same saved my engine.

Not all terminal wear metals are "chunks"!

 

[alarmguy]

The manual calls for a 10/30 so you are fine with Rotella 5/40, its a light oil and shears down quickly to a 30.
You may be having a clutch issue and the oil is just exposing it.

Shared sump motorcycle manufacturers know the oil shears down because of the transmission and base their oil selection with that knowledge. The disadvantage is you can feel the shearing effect in rougher shifting but that is all part of a shared sump.

I personally never used Rotella 5/40, ALWAYS preferred conventional 15/40 oils where a 40 was called for and now use a 15/50 HEDO in the current bike.