How much oil/ATF in my xs1100 sg?

[crazy steve]

...That is what the different numbers indicate on engine oil ratings 20W50 indicates it starts off at 50 and drops to 20 when hot...

Not true... there's been a lot of confusion on this (and you'll still find this erroneous info at places where they should know better). The 'w' after the first number indicates the actual oil 'weight' or viscosity, the second number is it's equivilent straight-grade load-carrying ability. So a 20W50 is a 20 weight oil that can carry the same load as a straight-grade 50W. This points up the importance of oil changes, as the 'higher' number is done with additives so if they break down, you can end up with straight-grade oil. There are some synthetics that muddy this definition, but if you're running dino oil this is accurate.

As to using ATF in forks, the main problem is the unknown viscosity. You can do a lot of suspension tuning with oil weight, but you won't know that with ATF...

'78E original owner

[DGXSER]

Thats pretty interesting Steve, as here is a quote straight form Castrol website.

"Center of the Donut – Viscosity Grade Identifiers
Right in the middle is where you can focus on viscosity, which relates to oil flow at different temperatures. Look for the SAE (Society of Automotive Engineers) mark. The lower the number on the left, the thinner the oil at low temperature, and the happier your engine will be in cold weather when it's time to turn over. The number to the right relates to higher temperatures. Higher numbers indicate thicker oil for better performance in the heat. The "W" stands for Winter Grade.

Multi-grade oils carry a dual-viscosity grade so they perform well in high or low temperatures. Now when you see identifiers such as 10W-30, 5W-20 or 20W-50 you'll know what it means – winter on the left (go lower), summer on the right (go higher). "

You may need to educate them on how they rate their oil. Or me on how to read what they have written here.

[oseaghdha]

Reading is fundamental

Yes, as Greg knows, oil viscosity changes with temperature. That is what the different numbers indicate on engine oil ratings 20W50 indicates it starts off at 50 and drops to 20 when hot.

.................

You got it bass ackward there chief.

[crazy steve]

I said you'll find this at places where they should know better...

Rather than believing everything you read, perform this simple test.

Buy a quart of 20W, 20W50, and 50W. Also pick up a simple viscometer, available at most paint stores. Pour a measured amount of each through the viscometer while at room temp, noting the amount of time it takes for each. While this won't give you a 'true' viscosity measurement such as API does, this will show you the relationship between the various weights.

Next, perform the same test, but after heating the oils to 200 degrees.

Now, if what Castrol (and others) says is true, in the cold test the two 20W oils will flow through in roughly the same amount of time, while the 'plain' 50W will take more time (being obviously, visibly thicker). After heating, all the oils should flow faster, with the 20W being fastest, and the 20W50 and 50W should now flow approximately the same (the 20W50 has supposedly 'thickened' to 50W, right?).

Is that what you'll find? No. In the real world, after heating the two 20W oils will still flow about the same, and the straight 50W will still flow slower than either 20W. The only oil I've heard about that supposedly violates this is some race-only 'straight grade' full synthetics from RedLine; they sell a 50W that they claim will match cold flow characteristics of thinner oils, but like Amsoil, they don't use the 'standard' API tests to determine 'weight'. So whether or not if it's a 'true' 50W is open to debate.

So if you can get different results, I'd love to hear about it...

'78E original owner

[crazy steve]

Actually, you don't even need a viscometer; use a small container (anything will work as long as you can put a measured amount in it) and drill a small hole in it, say a 1/4" hole. The thicker the fluid, the slower it will run out...

'78E original owner

[DGXSER]

All I know for fact is that we performed that very test with a viscosity gage in thermodynamics class in college. And yes, viscocity drops when temp goes up on motor oil.

I now your a smart person, however I hope you can understand where I might be defensive and question you for telling me everything printed by the folks who produce the substance your claiming to know more about is wrong, and that my personal experiments performed in a college laboratory are also wrong.

But, I suppose anything is possible. Back to the regularly programmed thread.

[crazy steve]

All I know for fact is that we performed that very test with a viscosity gage in thermodynamics class in college. And yes, viscosity drops when temp goes up on motor oil.

I now your a smart person, however I hope you can understand where I might be defensive and question you for telling me everything printed by the folks who produce the substance your claiming to know more about is wrong, and that my personal experiments performed in a college laboratory are also wrong.

The highlighted part above is what I'm saying, I'm not disagreeing with you or what you demonstrated in college; in fact, I'm agreeing with you.

What I AM disagreeing with is the claim made by many that multi-grade oil 'thickens' when it's temp goes up. Now, heat may 'activate' the additives that allow it to carry the higher 'weight' rating (and that seems to be the gist of some of the 'technical' expanations I've seem), but my point is, it doesn't actually get thicker. Why you find this misinformation, I can't say; maybe they feel the truth is too complicated? I worked for SoCal (now Chevron) years ago, and one of the classes I went to was all about lubrication. The engineer that taught the class gave the explanation I used; I've talked with shills at swap meets/car shows in the years since that claimed it thickened, but not one of them was able to demonstrate it, and a few tried. I run 20W50 in pretty much all my vehicles, but I do have one that does use straight 50W, and when draining hot oil, that comes out very noticeably slower.

'78E original owner

[XSokieSPECIAL]

Geeze Suckerpunch

Geeze Suckerpunch.............





Just LOOK at what we've started !!!!!!!

[DGXSER]

Ok...I am just going to shut up gracefully instead of continueing a bad situation and say I hate oil threads.

[Suckerpunch]

well it was suposed to be a oil amount thread

Im learning a couple things along the way

[XSokieSPECIAL]

It doesn't hurt to stir it up a bit, you can learn some good stuff. I always do 'cause there's some really smart people here (just ask 'em they'll tell ya!) that you can really learn some great stuff from.

I've learned a great deal here and appreciate every tidbit.

Before I start MORE trouble...heh heh heh....Thanks to all of y'all!

OK Suckerpunch..........ready for a tire thread ......or better yet....hardtails....LOL....

[Suckerpunch]

oops I started a balance beads in tires thread before reading your post.

It doesn't hurt to stir it up a bit, you can learn some good stuff. I always do 'cause there's some really smart people here (just ask 'em they'll tell ya!) that you can really learn some great stuff from.

I've learned a great deal here and appreciate every tidbit.

Before I start MORE trouble...heh heh heh....Thanks to all of y'all!

OK Suckerpunch..........ready for a tire thread ......or better yet....hardtails....LOL....

[XSokieSPECIAL]

oops I started a balance beads in tires thread before reading your post.

OH CRAP!.......Now you did it.......the discussion forum will get locked out now too!