dr oil duties ?

Joined
Apr 26, 2007
Messages
9
Likes
0
#1
What all does the engine oil do. I know it lubes the engine, but is it also the transmission oil and for the clutch? Thought I had read this earlier and tried to do a search but still came up with muddy answers. If the engine oil doesn't do the clutch and tranny, where would I change those fluids? Thanks in advance.
 

trial_07

Play with gravity
Joined
Apr 26, 2004
Messages
1,432
Likes
0
#2
What is your bike?
 
Joined
Dec 31, 1969
Messages
29,298
Likes
771
Location
Dallas
#5
You don't add a sig. The info goes in your profile.
 

SFO

Lifetime Sponsor
Joined
Feb 16, 2001
Messages
2,001
Likes
0
#6
Just use your owners manual they will cover the oil change pocess.
One oil for everything lubricated inside your motor.
What oil does is cool, lubricate, and carry swarf.
 
Joined
Jan 27, 2000
Messages
6,959
Likes
42
#8
olderndirtmom said:
Swarf?
Que?
Tell me please, could this "swarf" make fresh oil black, when adding oil to existing oil?

Mom.

The 'swarf' consists of metal and fiber particles worn from the engine and carried in suspension by the oil. When you change your oil, this swarf is dumped with the old oil. When you add oil to existing oil, the swarf remains in the existing oil. That is why it is so important to change your oil often.

BTW. Love your new avatar. ;) :cool:
 
Joined
Apr 28, 2007
Messages
424
Likes
1
#9
Thanks 89r. I was hoping you'd find this. After it turned black, I drained the whole thing just to be safe. Then put in totally different oil. (I can't get a new filter until tomorrow. It wasn't due for a change for another 100 miles or so, but was low.) It looks okay now, but it took an awful lot of oil compared to what the manual said it would require. I'll take it for a spin late this afternoon. I will change it again when I can change the filter. The looks of it spooked me! Theoretically it is still in the break in...and...I uh, violated a few of the rules for break in, I guess. And at least one other possible no no.

Nothing like prompt negative reinforcement to catch your learning attention!! ;) I tried reading up on oils last night in the wee hours to rule out the "no no"...but my eyes were heavy....

It's things like this why I started small, inexpensive, and manageable.

Thank you!

p.s. re avatar: Someday I'm gonna find one of that crazy cat on a bike. Be the cat... I mean bike.
 

Jaybird

Apprentice Goon
Joined
Mar 16, 2001
Messages
6,452
Likes
0
Location
Charlestown, IN
#10
Many will judge an oils integrity by the black color. And it is sometimes a key that the oil has indeed worn out it's welcome. But, some oils will have high amounts of detergents/dispersants that are in the mix to help clean the "swarf" and carbon deposits, and carry them in suspension and keep them there. This is a good thing, as it is much better for those things to be held up in the oil, rather than sitting in the corner of the engine creating a gooey sludge.

I have seen heavy duty engine oil, such as used in many diesel fleets, (rotella T, Delo 400, Delvac, etc) that turned a very dark blackish color in no time flat. This is due to it doing it's job very well, and not due to it being worn out.

The key to the oil change interval is the "swarf" that these shared sump engines create. No matter what the manual, or anyone else tells you, you need to change the oil out early and often.
Your engine will be far better off if you change out a cheaper oil after every other ride or so, than you would to use the most expensive moto-specific synthetic oil you could buy, and change it out only on occasion.

Shared sump engines get the oil dirty before it is worn out. And as a result we need to change the oil before it starts to degrade. This will conflict with many bike mfg manuals.
But never kid yourself into thinking that the bike manual is the tell-all bible of your bike. They make many mistakes when publishing these documents...especially when they are being translated into anther language.
 
Joined
Apr 28, 2007
Messages
424
Likes
1
#11
Jaybird,

I understand what you are saying. And by shared sump you are referring to the fact that my oil serves multi purpose: tranny/clutch/engine and so the grit from one goes into the other as it circulates, yes?

My dumping the oil that turned black was two-fold concern, and maybe you can help my understanding with this. To those of you who will be easily horrified at my ignorance, please cover your eyes and read no more.

I've read, cursory, bleery eyed mind-you, the meanings of the SAE numbers, and the informative DRN thread on the difference between tranny oil and engine oil, which actually went a long way to furthering my knowledge...but never came up quite with the answer I was looking for before I needed to sleep. I haven't had a chance to keep looking by light of day, so, I'll go out on the line here and just ask.

The manual calls for 10w-40. I understand the meaning of the various numbers. I presume that was what was in the engine at time of purchase. I purchased it with 12 miles on it, so most of the miles are my miles. I just assumed the bike was set up properly... maybe an error on my part...As I said, it was in the break in period. To date, I used it only on the road, not on dirt. Although the first twelve miles are anyone's guess.

I exceeded pretty much all the break-in rules on speed, throttle position, rode it in December, never winterized it, rode it in early spring, etc. etc. The oil was low...but, what droplets appeared through the view window were normal oil color....Then I threw in 20w-40 yamalube. Turn engine on, instant black.

So, presumably this was no chemical reaction then in the sense of two incompatible oils? "Merely" picking up swarf from the fact that I undoubtedly abused the little baby during it's settling period? Not burned on crust from the fact I let it get (too?) low? How bad is it, doctor, and is she gonna live? ;)

Like I said, I drained it, and refilled with 10w-40....Nice and pretty now. I've not taken it out yet. Will change filter and oil again shortly.

Thanks in advance for clarifying. The rest of you can uncover your eyes now. ;)
 
Last edited:

Jaybird

Apprentice Goon
Joined
Mar 16, 2001
Messages
6,452
Likes
0
Location
Charlestown, IN
#12
OK...this is simply my take on this.
Our bikes don't hold much oil to begin with. Normally most dirt bikes will hold less than a full quart. The small volume of fluid has a great load placed on it, especailly when used in a four stroke bike that requires the lubricant to protect both the clutch pack as well as the engine components, such as valves and bearings.

When a big load is placed on engine oil, it tends to shear it down. Meaning the action of the engine parts, like gears meshing and metal components sliding on one another, causes the oil to be thinned out to a thinner viscosity than it was originally in a very short period of time.

This thinning of the oil, and the heat that the small amount of oil sees, places a big demand on the additive package to protect past what the base oil can.
And the life of the additive package becomes less and less with more work. The additives can also become depleted due to the oil oxidizing. When the oil starts to oxidize it will become increasingly acidic, and this acidity tends to break down and deplete the add pack, as well as the work does.

This is the reason you will hear oil change recommendations containing a time factor as well as a mileage number.
Even oil that is doing no work at all can become less and less effective simply by sitting idol in the engine, due to the oil is always degrading and the acidity is always working to break down the oils protecting properties.

Another big issue with dirt bikes is that they typically will produce alot of blowby of combustion gasses that can blow past the rings of the piston. And along with carbon, raw fuel can also enter into the oil sump, which dilutes the oil and helps to break it down faster.

Workload, heat, contamination (carbon, fuel, and "swarf"), as well as time, are the enemies of engine oil. And the best way to combat these ill effects on the oil, is to change it out on a very frequent basis.