Engine Types and Oil Specs

[Jay Freddy]

Apologies in advance if this seems to be a naive question. I'm not an engineer, just a guy who likes to ride and occasionally wrench...

I'm curious as to what kinds of oil specifications go best with different types of engines, particularly with regard to motorcycle engines.

The starting point should be to follow manufacturer recommendations, but are there other guidelines by which we can compare different oils, regardless of brand?

For example, large air cooled engines seem to prefer heavier oils, e.g., 10w50 or 20w40, etc.

I suspect that most racing engines are using much lighter oil, eg. 5w20, etc., with shorter OCI's.

Honda is now recommending 10w30 across the board in all of their machines, including engines that were previously spec'd for 10w40.

I don't see any air cooled engines in Honda's current product offering.

So what specific qualities should we be looking at in VOA's to determine suitability? TBN? Flashpoint? HTHS?

I get bored when people trot out their favorite brand names. I'd like to know what are the qualities to look at, regardless of brand, that are good for specific purposes.

Thanks in advance to the smart guys here who have the patience to explain it to the rest of us!

 

[midobo]

No need to look at VOAs to determine suitability because they won't tell you anything. You covered it at the beginning of your post. Owners manual states oil specifications they recommend. Buy oil that meets those specifications. Anything else is just... Well, it's BITOG.

 

[Jay Freddy]

No need to look at VOAs to determine suitability because they won't tell you anything. You covered it at the beginning of your post. Owners manual states oil specifications they recommend. Buy oil that meets those specifications. Anything else is just... Well, it's BITOG.

I'm not buying that.

The Honda manual recommends Good 'Nuff 4 Honda oil because it creates an extra revenue stream for them.

Honda owner's manuals recommend Honda GN4 10w30 for all their engines. 10w40 for hot climates.

Being a Japanese company, they're fully onboard with the JASO MA standards too.

It wasn't always like this.

In my air cooled CB1100, I ran the GN4 for 4000 miles/one year the very first year I owned it.

It came out looking like burnt coffee. Completely black with almost no remaining viscosity.

I didn't do a UOA, but it flowed like water, it was obviously sheared down.

If I had tried to go a full 8k miles as Honda recommends, I'm convinced that it would have done irreparable harm to the motor.

I would like to know what are the specific qualities that make some oils better suited to a certain task or environment.

Why did the GN4 cook down so much?

I'm not trying to bash the GN4. I'm sure it works fine for most liquid cooled engines.

Rather than talk about brand names, I want to know why some oils perform better than others.

 

[PWMDMD]

I'm not buying that.

The Honda manual recommends Good 'Nuff 4 Honda oil because it creates an extra revenue stream for them.

Honda owner's manuals recommend Honda GN4 10w30 for all their engines. 10w40 for hot climates.

Being a Japanese company, they're fully onboard with the JASO MA standards too.

It wasn't always like this.

In my air cooled CB1100, I ran the GN4 for 4000 miles/one year the very first year I owned it.

It came out looking like burnt coffee. Completely black with almost no remaining viscosity.

I didn't do a UOA, but it flowed like water, it was obviously sheared down.

If I had tried to go a full 8k miles as Honda recommends, I'm convinced that it would have done irreparable harm to the motor.

I would like to know what are the specific qualities that make some oils better suited to a certain task or environment.

Why did the GN4 cook down so much?

I'm not trying to bash the GN4. I'm sure it works fine for most liquid cooled engines.

Rather than talk about brand names, I want to know why some oils perform better than others.

Was the engine warm when you changed the oil? What does almost no remaining viscosity mean and how do you know that? Is it possible for any engine to shear an oil down so much in 4,000 miles that it flows like water?

 

[zrxkawboy]

I'm no expert, but I can share my opinion (FWIW) and experiences. I'm not sure there is a way for the average rider to determine which oil will work well in their bike without trial and error. For example, a few years ago, I had picked several quarts of 10W40 Quicksilver Motorcycle oil on sale at the local WM. It was labelled as full syn, so my thinking was that a name brand, full syn, MC-specific oil should be pretty good stuff. I put it in my dirt bike for a couple of OCIs, and it was fine at first, but shift quality seemed to deteriorate rather quickly. (I ride a stock bike, and I'm just an old guy out having fun...no racing or anything.) Next, I tried the Castrol Actevo that I'd been using in my ZRX1200, and the shift quality stays consistent for much longer. The Actevo is labelled as a blend, yet gives me better results than the Quicksilver full syn.

I know, using shift feel is very subjective. I have no UOAs to determine if the oil was shearing. Could it be my specific bike, or even my imagination? Anything's possible. But, based on my experience, I now run the Actevo, and gave away the remaining few quarts of Quicksilver.

 

[Jay Freddy]

I'm no expert, but I can share my opinion (FWIW) and experiences. I'm not sure there is a way for the average rider to determine which oil will work well in their bike without trial and error. For example, a few years ago, I had picked several quarts of 10W40 Quicksilver Motorcycle oil on sale at the local WM. It was labelled as full syn, so my thinking was that a name brand, full syn, MC-specific oil should be pretty good stuff. I put it in my dirt bike for a couple of OCIs, and it was fine at first, but shift quality seemed to deteriorate rather quickly. (I ride a stock bike, and I'm just an old guy out having fun...no racing or anything.) Next, I tried the Castrol Actevo that I'd been using in my ZRX1200, and the shift quality stays consistent for much longer. The Actevo is labelled as a blend, yet gives me better results than the Quicksilver full syn.

I know, using shift feel is very subjective. I have no UOAs to determine if the oil was shearing. Could it be my specific bike, or even my imagination? Anything's possible. But, based on my experience, I now run the Actevo, and gave away the remaining few quarts of Quicksilver.

I liked the Castrol Actevo 10w40 in my liquid cooled Aero 750. I'd buy it again if I couldn't get the Rotella 15w40.

Was the engine warm when you changed the oil? What does almost no remaining viscosity mean and how do you know that? Is it possible for any engine to shear an oil down so much in 4,000 miles that it flows like water?

Yes. The engine was warm, but it's the same way I've always dumped old oil before an oil change.

When I dumped the used GN4, it was totally black, no opacity at all. It seemed like charcoal suspended in a very thin liquid...

I call this method the calibrated eyeball!

With my previous bikes (Nighthawk X2, KZ440 LTD, KZ250, ST1300, VT 750 X2), when I dump the oil, the color is dark, but typically it still has some opacity and retains some visible viscosity too.

Seriously, I believe I can see a difference between a thin sheared down oil and used oil that still has some life in it.

What I'm trying to understand is why one oil (GN4) breaks down while another (Rotella T5) stays viscose and maintains some visual opacity.

It's not because of the branding... There are obviously different properties of the respective oils that are causing them to perform differently.

 

[midobo]

I'm not buying that.

You should probably tell Honda they don't know what oil their engines require.

 

[Jay Freddy]

You should probably tell Honda they don't know what oil their engines require.

I have no doubt that Honda knows what their engines require.

It's their legal obligation to maximize shareholder value that assures me that there are better ways to choose oil than brand name alone.

 

[jeff78]

What I'm trying to understand is why one oil (GN4) breaks down while another (Rotella T5) stays viscose and maintains some visual opacity.

It's not because of the branding... There are obviously different properties of the respective oils that are causing them to perform differently.

Different VII's shear differently - some shear more, others shear less. If you still have some of that old oil, you can send it off for a UOA to see what the viscosity actually is.

The GN4 was a 10W-30? Or 40? Personally, I'd never run a 30 in an air cooled shared sump motorcycle engine, regardless of what the manual says. Minimum 40, and maybe upping to a 50 in hot summer months.

To answer your original question, I'd say there are only a few things on a standard VOA that are useful. Viscosity, TBN, and zinc/phosphorous quantities. HTHS, isn't something you'd normally find on a VOA - you'd have to pay extra for that testing if the lab even offers it.

VOA's don't really tell you much about 'suitability'. If someone gave you VOA's for 2 different motor oils, other than maybe the viscosity values you would not know which oil will work better in your bike. It won't tell you which one will shift better new, or which one's shifting will go to crap sooner than the other's.

So it really does just boil down to trying a bunch of different oils and seeing which ones you feel work best in your bike.

 

[Jay Freddy]

Different VII's shear differently - some shear more, others shear less. If you still have some of that old oil, you can send it off for a UOA to see what the viscosity actually is.

The GN4 was a 10W-30? Or 40? Personally, I'd never run a 30 in an air cooled shared sump motorcycle engine, regardless of what the manual says. Minimum 40, and maybe upping to a 50 in hot summer months.

To answer your original question, I'd say there are only a few things on a standard VOA that are useful. Viscosity, TBN, and zinc/phosphorous quantities. HTHS, isn't something you'd normally find on a VOA - you'd have to pay extra for that testing if the lab even offers it.

VOA's don't really tell you much about 'suitability'. If someone gave you VOA's for 2 different motor oils, other than maybe the viscosity values you would not know which oil will work better in your bike. It won't tell you which one will shift better new, or which one's shifting will go to crap sooner than the other's.

So it really does just boil down to trying a bunch of different oils and seeing which ones you feel work best in your bike.

Thanks for the thoughtful reply.

The GN4 I ran was 10w40. That's what turned into watery burnt coffee.

Honda recommends the 10w30 for this engine.

I have been running Rotella T5 10w30 for the past two years. Approximately 4k miles per year, and the T5 comes out still viscous and while dark, it still has a slight amber tint too

I was surprised that the Honda GN4 10w40 did so poorly. That's part of why I started this thread.

If there are specific additives or numbers to look at, that would be good to know.

Thanks again for a thoughtful reply!

 

[Bonz]

Mobil 1 10w40 4T. Gets as many positive reports as any, IMO and IME. Going back in the sump next change 'cause I have some in the garage and it flat works for 5,000 mile OCI's and gives me the "feel" I like.

As said above, different oils give different results ("feel") depending on the rider. Put two guys on the same bike back to back and they can have totally different reports. We all have preferences for shift feel, the way an engine sounds, color of oil in the sight glass or upon drain, etc.

As an example, currently I have Amsoil 20w50 metric in my ZRX1200, around 3,000 miles in the sump. It has a different feel vs the Redline 20w50, M1 20w50 and the M1 10w40 4T that have been run in previous OCI's. Analysis will show how it compares in a general sense, but I know from all the analysis around here that it's doing what oil should do for protection despite differences in my observations.

 

[Jay Freddy]

Mobil, Amsoil, Redline, Rotella, Castrol...

Seems like we're back to talking about brand names.

Sorry about that.

 

[Pete in PA]

Honda used to always have the temp. chart for what oil to use. It allowed from 10-30 to 20-50. Now all of the sudden, with no engine changes, it's 10-30 across the board. I don't agree. Especially if it's an air cooled engine.
Now oils have improved a lot since the 80's but 10-30?
I use 10-40 syn. motorcycle oil in my 92 750 Nighthawk.

 

[jeff78]

Mobil, Amsoil, Redline, Rotella, Castrol...

Seems like we're back to talking about brand names.

Sorry about that.

Well, they all have their own 'recipes' which they don't disclose, so how else would you refer to them?
It would be like talking about chocolate without mentioning brand names.

 

[Jay Freddy]

Well, they all have their own 'recipes' which they don't disclose, so how else would you refer to them?
It would be like talking about chocolate without mentioning brand names.

Just like @Pete in PA and you did above!

To use your analogy, one could talk about chocolate referring to things like percentage of cocoa, amount of sugar, amount of milk and or dairy ingredients, lecithin, carrageen, etc.

But you'd need to be a true chocolate geek to care about that stuff!

 

[BusyLittleShop]

If there are specific additives or numbers to look at, that would be good to know.

Thanks again for a thoughtful reply!

Here are the specific additives that are good to know when comparing Mineral Honda 10W30 @ $13.67 quart and Synthetic Mobil 1 5W30 Auto @ $5.00 quart... Either one will meet and exceed your mileage expectations...

 

[Bonz]

Honda has 15% more zinc and 40% advantage in boron and 15° higher flashpoint. Only advantage M1 has is moly. That's three to one on advantage, Honda. Where the heck are YOU buying M1 5w30 auto (not even an MC oil!) for $5 a quart? 10w30 Honda is $8.67 from Partzilla currently. Pure misinformation to advance a consistent agenda on your part.

5W30 isn't recommended in any motorcycle to my knowledge. Once AGAIN useless (misleading) information. (edit - MOD)

That you post these this crud and people who don't pay attention may bite, is a disservice where honest discussion and honest presentation is valued. This type of egregious post brings none of that.

 

[kschachn]

Honda has 15% more zinc and 40% advantage in boron and 15° higher flashpoint. Only advantage M1 has is moly. That's three to one on advantage, Honda. Where the heck are YOU buying M1 5w30 auto (not even an MC oil!) for $5 a quart? 10w30 Honda is $8.67 from Partzilla currently. Pure misinformation to advance a consistent agenda on your part.

5W30 isn't recommended in any motorcycle to my knowledge. Once AGAIN useless (misleading) information. (edit - MOD)

That you post these this crud and people who don't pay attention may bite, is a disservice where honest discussion and honest presentation is valued. This type of egregious post brings none of that.

Plus the fact that he's been posting that same analysis for years and there's zero likelihood it is still accurate.

 

[Bonz]

I agree, this forum is about pertinent dialogue and information. It is a tall task to monitor for the mods and I should back off a bit with my choice of wording. I appreciate they left the main part of my post intact that conveys the message of inaccuracy that exists to a high degree. It's important to look out for not only each other, but those that may come after and read these threads.

 

[BigCahuna]

Back in 1976, I bought a brand new Honda gl 1000 goldwing. The manual for that engine said to use a good API rated oil in it. There was no Jaso ratings at that time. It ran fine on that rated oil I used in it. Every air cooled bike I've ever owned called for 10w40, or 20w50 wt oil. The last water cooled bike I had, a 2016 kawasaki Voyager, called for 10w40 wt jaso ma2 or Api sm rated oil. Again it ran fine on that oil. Kawasaki also said that 10w40 should be fine in all situations, and didn't really want the owner to use a heavier oil. I used Valvoline metric oil. No consumption issues ever. My 2006 Harley Police bike gets whatever 20w50 wt oil, that's priced the best at the time I'm in Advanced auto parts. I've used just about every 20w50 wt oil out there, and I've never had an issue with any of them. I believe the mfgrs spec an oil to be used based on how low the performance will be, at a given mileage. It has to last thru the warranty period, and not allow major damage in the lifespan of the bike. Of course if you ride the bike like a hooligan, or race it on track days, all bets are off. Then the boutique oils step in to say their oils allow your bike to last 400,000 miles, being raced every day. And if something lets go, it's either the bike is crap, the engine was made wrong, or the oil couldn't handle the task. If you ride your bike like a sane person, use a decent oil and keep the oil topped off, Most bikes will last longer than the owner will want to own them.,,,