HDEO Oils and Foaming

[alex_at]

Hi,

I often read that car oils are prone to foaming in motorcycle engines, even some motorcycle oils are suspected to foam up. I know a lot of people (me now included) use HDEO oils in their motorcycle. But why are HDEO's not foaming? Do they contain the right amount of anti foam additive that happens to be enough for motorcycles too?

Why are HDEO's not foaming but some car and motorcycle oils do tend to foam?

 

[Doog]

I have used only MC oils in my bikes...never foamed. I have used:

HD syn3 20w50
Mobile1Vtwin 20w50
Castrol 4T 10w50
Redline 20w50

 

[SonofJoe]

All engine oils, be they PCMO or HDDO, all in theory need to pass the same industry standard foaming tests and all should contain exactly the same amount of siloxane polymer antifoam. In other words, there shouldn't be a difference. However diesel oils tend to contain a lot more additive and antifoam used in the manufacture of additive can often 'creep' into the finished DI package and impart 'extra' antifoam to a diesel oil. So in practice, it may well be that HDDOs are better in high revving bike engines.
Hope that helps...

 

[dareo]

I found RTS 5w40 to outperform Mobil 1 Motorcycle oils in my old Suzuki DR350. I rode it even in winter and it would cold start and shift brilliantly off that tiny motorcycle battery. I wasn't looking for foam but like i said it ran really nice.

 

[Papa Bear]

I think that was more of a problem in dry sump engines (like my 1965 BSA Lighting Rocket 650)

That's what Jim Robinson told me.

 

[CT8]

HDEOs started needing really high anti foam protection when Caterpillar HEUI engines came on the market.

 

[BigCahuna]

In cars the lubrication systems pull their oil from the bottom of the oil pan, and any foam is usually seen on the top of the oil pan. So, unless there's NOTHING but foam in the oil pan, how would this mean anything to the lubrication of the motor? The same goes for motorcycles. Oil is either drawn from the bottom of the oil tank, or gravity feed from the bottom of the oil tank into the oil pump. If foaming was an actual problem ,you would hear about motor damage to millions of vehicles all the time. Seems people need to invent things to worry about.,,,

 

[bonjo]

not all oils are the same. car engine oil has to meet different need to wet clutch motorcycle oil.

IN notorcycle with Highe reving engines and wet clutch foaming and shearing are significant compared to car engines.

Imagine beating egg white with a fork (as in car engine) compared to a hand mixer (as in motorbike engines) the outcome is very similar.

If HDECO oil is different, then I don't know why. But for me it is immaterial as I always use motorcycle oil.

 

[donnyj08]

I stopped and checked my oil after 100mi straight on the interstate. The top 1/4" of the sight glass was foamy... I'm using Delvac 15w40

 

[AMC]

Originally Posted By: donnyj08
I stopped and checked my oil after 100mi straight on the interstate. The top 1/4" of the sight glass was foamy... I'm using Delvac 15w40


That will happen no matter what oil you use, it is normal on most bikes. There can be anything from just a few bubbles to a layer of foam on top of the oil. If your entire sight glass is light colored foam, then you have a problem.

You may want to make sure that your sump is not over filled. Over filling can result in more foam.

In your case where there is just a little foam on top; Remember that the oil pickup is towards the bottom of the oil pan, where there won't be any foam. So it won't be a problem either way.

 

[donnyj08]

Originally Posted By: AMC
Originally Posted By: donnyj08
I stopped and checked my oil after 100mi straight on the interstate. The top 1/4" of the sight glass was foamy... I'm using Delvac 15w40


That will happen no matter what oil you use, it is normal on most bikes. There can be anything from just a few bubbles to a layer of foam on top of the oil. If your entire sight glass is light colored foam, then you have a problem.

You may want to make sure that your sump is not over filled. Over filling can result in more foam.

In your case where there is just a little foam on top; Remember that the oil pickup is towards the bottom of the oil pan, where there won't be any foam. So it won't be a problem either way.


]XSR900 foam[/url]

so this is normal?

 

[SlipperyPete]

Try something that meets the oil requirements listed in your owners manual and see if there is a difference. That doesn't look normal to me.

 

[bulwnkl]

Don't know whether that's 'normal' for your bike. Never saw anything like that with my CBR, and and have never seen any foam of any type on the dipstick of my NCX.

 

[JonfromCB]

The above posts from sonofjoe and CT8 supporting the notion that HDEO's have more anti-foaming agents than oils blended for gas engines is contrary to what I've heard, read and understand about diesel rated oils actually having less anti-foaming agents simply because diesels don't need as much anti-foaming agents as gas engine oils. I've also read some papers and studies specifically related to how foaming in shared sump motorcycles is detrimental to transmissions...and gear pitting.

Having had lots of bikes over 46 years I sure wouldn't keep that oil in any of my bikes. I would not be surprised by UOAs on oil forming that badly also indicating rapid shearing and lots of transmission metals.

I also don't agree with AMC's post saying it's normal on most bikes. In fact I've never seen foaming like that on any bike.