Extending OCI's on a Husaberg

[wescat]

I have a motorcycle that I ride as a "Dual Sport", a 2007 Husaberg FE550E, and it will darken the motor oil very quickly. It has a 4 stroke high performance engine with forced oil lubrication, one full flow oil filter, an oil screen on the pump suction, a magnetic drain plug and oiled foam air filtration. The engine and transmission share the same oil, and all of the gears are straight cut. The engine vents blow-by via a molded rubber hose to the air box. The sump holds one quart of oil, the manufacturer's owner's manual specifies a JASO T903 MA 10W50 oil, and specifies an OCI of every 15 hours/100 liters of fuel. I currently use Shell Rotella T4 15W-40. The motor oil will get very dark within that OCI.

So...

1. What exactly causes motor oil to darken with run time?
2. What are the correlations between motor oil darkening and desirable oil property degradation?
3. Reading motorcycle forums, the conventional wisdom on this issue is to change oil frequently.
4. It is commonly believed that viscosity breakdown occurs due to shear via gear mesh. Is this correct?
5. If it is correct, how does the viscosity breakdown correlate to increase wear within the engine?
6. Should I utilize oil analysis to determine the best OCI?
7. If yes, what analysis criteria should I set the OCI upon?
8. I am curious what I can do to extend OCI's on this MC.
9. Would increasing the sump capacity have much effect?
10. Would bypass oil filtration have much effect?

Any and all input is greatly appreciated.

 

[Cujet]

Carbon from combustion, generally called "soot" causes the oil to become black. Soot particulates range in size from sub micron up. The larger soot particulates can increase wear rates on some components. Gasoline in raw form also sneaks past the piston rings and contaminates the oil. Most of the gas evaporates, however, over time the heavier components of gasoline accumulate in sufficient quantity to dilute the oil with non lubricants. It's for this reason that bypass filters are not an ideal answer for some engines.

Yes, motorcycle engines can generally use frequent oil changes. Failure to do so is a good way to increase wear rates.

Viscosity is how oil protects your engine. Any oil with a viscosity index improver will shear rapidly in motorcycle transmissions. A 10W-50 or 10W-60 oil very likely contains VI's.

UOA is a great tool. However, is is my opinion, based on empirical evidence, that a conventional UOA is insufficient to determine wear rates (that requires direct measurement) and is insufficient to determine an oil's continued suitability in some/many cases. As UOA's typically do not contain detailed particulate counts (and therefore you don't know if you have large, wear promoting particulates)

It's not unusual for oil that's been in the sump WAY TOO LONG, to come back with superb UOA results. A great example is the GM balancer chain wear rates and associated good UOA's. Sure, the rest of the engine was fine...... except the highly loaded and difficult to change, balancer chain. More frequent oil changes and a move to higher viscosity, solves the problem.

An oil change is the only viable way to remove contaminates. Period, end of story.

Yes, a larger sump can reduce oil change frequency.

With such a small sump, frequent changes are a very good idea.

 

[IndyIan]

High performance 4 stroke dirt bikes are one example of where extending the OCI can be a really bad idea. Unless you putter around town at 35 mph or less, that oil is under quite a bit of stress. My ATV has half the displacement,1/3 the HP, an oil cooler, and it has a 4L sump... On that I don't feel bad extending the OCI.
Why do you want to extend the OCI? Are you commuting on it and don't want to change the oil every week? For what that oil costs, especially in a 20L pail, I'd just change it frequently, and save your money for good tires.

 

[CT8]

1) Heat , contaminants and blow by.
2)It is hard to tell without an oil analysis.
3)Yes clean oil is happy oil, lots of stress on a shared sump M/C.
4)Yes as well as the engine Most m/C engines are sporty.
5)The oil becomes thinner, there then is thinner film keeping the parts separated.
6)Why spend the money on the oil analysis when clean new oil is better.
7)Buy new oil instead of an oil analysis .
8) Don't extend the oil change interval.
9) Yes but how and why?
10)Not really the oil capacity would be increases, the oil will be a bit cleaner but the oil would still be beat up by the engne and trans, Would the oil pump put out enough volume to feed the bypass filter and the engine ?

 

[wescat]

Originally Posted by Cujet


With such a small sump, frequent changes are a very good idea.


Understood, that is good advice, thank you.

 

[wescat]

Originally Posted by IndyIan

Why do you want to extend the OCI?

I've been considering long rides on it, like the TAT, and in that scenario an extended OCI would be beneficial.

 

[wescat]

Originally Posted by CT8
A. ...but the oil would still be beat up by the engne and trans.
B. Would the oil pump put out enough volume to feed the bypass filter and the engine ?

A. Very true, salient point.
B. I believe that the oil pump could keep up. I wouldn't know until I tried to install one, though.

 

[ZeeOSix]

Originally Posted by wescat
Originally Posted by Cujet

With such a small sump, frequent changes are a very good idea.

Understood, that is good advice, thank you.


Obviously, with only a 1 qt capacity it's why the manufacturer recommends 15 hr oil changes.

Are you using full synthetic motor oil?

 

[wescat]

Originally Posted by ZeeOSix
Originally Posted by wescat
Originally Posted by Cujet

With such a small sump, frequent changes are a very good idea.

Understood, that is good advice, thank you.


Obviously, with only a 1 qt capacity it's why the manufacturer recommends 15 hr oil changes.

Are you using full synthetic motor oil?

No. As stated in the OP: " I currently use Shell Rotella T4 15W-40" which is a non-synthetic, conventional oil: https://rotella.shell.com/en_us/pro...d0fc768d05faab7059e52f0938/t4-15w-40.pdf

 

[ZeeOSix]

^^^ If it was me, I'd try to find an appropriate full synthetic to use if there's only a 1 quart sump capacity. It will help give a bit more protection from oil breakdown from heat, etc.

 

[Shannow]

My brother had a husaberg...you need regular oil changes to flush the camshafts out of the sump.

 

[IndyIan]

Originally Posted by wescat
Originally Posted by IndyIan

Why do you want to extend the OCI?

I've been considering long rides on it, like the TAT, and in that scenario an extended OCI would be beneficial.

Yeah, in a situation like that I think I would run the filter for two OCI's. Without the messy filter change, just changing the oil could be done pretty easily on the road? You might want to enlarge the hole in the skid plate for clean drainage or something like that. Atleast on my ATV, the filter doesn't seem to close to "full" of gritties, but ymmv.

 

[DoubleWasp]

Increasing the oil capacity is a great idea. I have two bikes. One that was available with or without frame oil. I have the frame oil version, and the engine oil runs a lot cooler than the model without and goes significantly longer on oil changes than the model without (by manufacturer specs).

The other bike has a tiny sump capacity, but I installed a case oil cooler that also nearly doubles the oil capacity. Oil runs significantly cooler, and can go a lot longer on an oil change as well. Don't know anyone riding enduro on a 525 that doesn't punch out the oil capacity.