YZ450F Oil Life

Well this is a good thread to ponder in. As always a very educational oil thread with the help of gray racer.

My question is about the additive/stabilizer Lucas produces. Has anyone used it in a off road motorcycle, more particularly the yz 450.

I use the stuff in my vehicles, simply because the first time I used a quart of it in my '65 Chevy with the original 283 v8, I noticed less valve train clatter/lifter noise, I also noticed higher sustained oil pressure by about 15 - 20 lbs, throughout the full tempature range of the oil. By full tempature range, I mean Arizona summer heat, freeway cruising at 3k rpm. :banghead::busted:

As I was changing the oil in my truck last weekend I was reading the bottle, and it stated it was acceptable to use in a wet clutch motorcycle application, up to 20%.

I have heard quite a bit about Lucas' oil stabilizer from independent sources, all of it negative. The gist of it is that it contributes to foaming, and does nothing to increase the shear stability of the oil. It claims to contribute to better lubrication by giving the oil the ability to cling to the rotating parts (witness, the little gear/crank displays at the auto parts stores). However, that tendency is not always desirable. Excess oil windage of a crank can sap a considerable amount of HP, and possibly interfere with proper scavenging and cylinder lubrication.

I wouldn't use it.

any info on motul 300v? I have been using motul 3000 the last few years in other bikes.

Just got a Yz450f 03. I have been loving this form so much to take in.


In the Amsoil test, Motul 300v Sport (10w-40) dropped quickly from a mid-40wt to the lower limit of SAE 40 (12.5 cSt), but not below that, and did very well in other respects overall. Motul 300v Comp (15w-50) held up quite well in terms of viscosity retention.

the oil came back from Blackstone at an SUS viscosity of 67.1, very much still a 40 weight oil. The longest other oil sample I have run was about 7.5 hours on Mobil 1 MX4T (which is now sold as "Racing 4T"). It returned at 66.8.

took me a while but, these are not in grade.

a susvis of 67.1 converts to a cSt of 12.172, which is below the API standard of 12.5 cSt for a 40wt oil.

the 66.8 converts to a cSt of 12.091 which is also below mark.

here are the links to the appropriate tools to verify yourself.

API Engine Oil Classifications:


susvis <- -> cSt conversion tool and equation:


Depends on who's converting SUS to cSt. Blackstone sent back both samples (among others) with "65-78" in the "Values Should Be:" field under SUS viscosity @200 F. On top of that, you've caught an error I made; the Amsoil number should have been 69.1, not 67.1

Saybolt Unversal Seconds (SUS) is a dated, and somewhat crude means of measuring viscosity that amounts to nothing more than measuring the amount of time it takes for a known quantity of oil to drip through an orifice of a calibrated size. The fact that they still use this method is one of the things I dislike about Blackstone, but their service is good. I'd much rather have the viscosity expressed in Centistokes, but at this point, I don't have a lab to do that.

Note that the gist of the entire article you referenced is that oil testing is imprecise. It is also true that there is no one formula that will accurately convert SUS to cSt, since the formula has to be adjusted in a non-mathematical manner as the range of viscosity changes. Published tables converting these two units also tend to differ. Either way, Blackstone said both samples were in grade.

We'll see how this next batch goes.

Bear in mind that I did say "nearly" 10 hours, and that the ability to reach that figure is dependent to a great deal on what kind of riding one does for ten hours. In one sample I took of used Amsoil MCF (10w-40 "Synthetic Motorcycle Oil") from my '03 YZ450 at 9.4 hours of fast trail and desert riding, the oil came back from Blackstone at an SUS viscosity of 67.1, very much still a 40 weight oil. The longest other oil sample I have run was about 7.5 hours on Mobil 1 MX4T (which is now sold as "Racing 4T"). It returned at 66.8. By comparing the virgin samplings of these two oils, the resulting drop in viscosity was around 6 and 10%, respectively, which is good in its own right, and even better since they were still in grade.

Also, if you read the post I linked to, you'll see that I don't very often run my own oil that long, especially with a race involved. (It would normally be closer to 6). But it's comforting to know that the stuff won't roll over on me if it gets stretched a little, and it's a hell of a lot better than the results that Rotella or YamaLube will put up.

As to whether they are expensive, that depends on how much arms and legs go for in your area. Mobil1 Racing 4T is a very, very good oil, but it's a long way from cheap. As a preferred customer, I pay a net price including shipping of about $7/qt for Amsoil MCF, which isn't real cheap, either, but given that I can get 2-3 rides out of it, I think it works out within my range of acceptability. You may disagree.

Another line of oil that produces very good results in ASTM D-6278 shear tests is the Synthetic Blend, Synthetic Extra, and Ultra oils from Maxima. The Synthetic Blend and Synthetic Extra have been pretty reasonably priced when I've seen them on the shelf.

I'm gonna the Mobil Racing 4t

I change the filter and oil after a weekend of riding about 6-8 hours don't forget that air filter is very important too

That isn't as true as you might think, and the fact is that the Feds are interested in things that we aren't.

Dream on, I am a retired fed.

Most of the innovations if not all, come from private industry, and developed for consumer needs. Federal Government is nothing but another consumer.

I don't want to high jack the thread on Government Issues. Lets keep it oil.

If a consumer based test is done, and findings of the test is published. I believe in a forum of this many voices and consumers, a product will come to the surface that is so to speak "Best in quality".

It will be noticed.


I am riding my 2003 yz450 during the winter and was wondering what oil to use. In the summer I use Yamalub 20W40. Winter here in Canada is cold and I was looking for a 5w40 oil suitable for cold weather ice racing. Anyone have any ideas?

How does anyone feel about using the Mobil 1 V-twin 20-50 synthetic oil. Ive always ran 20-50 oil in my thumpers. my drz 400 would turn into black water at like 5 hrs.

The Mobil 1 motorcycle oils (V-Twin and Racing 4T) hold up very well.

The viscosity you see when you drain the oil is not an indication of how well the oil retains its viscosity. Multi grade oils all start with a base oil of the viscosity of the "W" number in the listed grade. For instance, 20w-50's start as 20 weight oil. Additives are then used to prevent the oil from thinning in a normal manner, so that at 200 degrees F, the oil is still as thick as a normal, straight grade 50 weight would be at that temperature. If these additives are damaged and viscosity lost, it will not be apparent until the oil is heated. The viscosity at low temps remains that of the base oil, and you won't be able to see any difference.

I guess my question would be that why not run a 20W50 instead of a 10W40 you already start out with a high viscosity of 20w compared to a 10w?

Because, the 50 weight oil is thicker than needed, and oiling systems work best when the lighter oils are used (delivered volume increases).

In the event that shear down is expected to be a problem, a 50 can provide a little more protection from that by starting out heavier. Then if the oils shears down a full grade, it's still a 40. That's not the best approach to take, however.

it all depends if your ringing your bike out all the time or not. I change my oil and clean the ss filter about every third ride. I reckin that a pro would change there oil about every ride since there wide open most of the time. if you are slower and puttin it wont need to be changed as often. it greatly depends on ride style.

I just changed oil in both my MX bikes. Both only has around 4 hours since last change.

For the YZ450f the oil came out looking like it went in.

For my CRF450f, the oil in the tranny came out light and clean looking but the engine side oil on the CRF came out black as night.

So just thinking the oil volume being so low in the CRF makes the difference. I think gray might have mentioned that before. It almost seems that I can watch my CRF oil change color. Maybe that is why they gave us the site glass..

Just making an observation..

The color of the oil may or may not tell you anything, and it isn't necessarily an indication that there is anything wrong. It is interesting that the same oil should come out looking differently from two engines.

Darkening of the oil can be nothing more than a reaction by some component of the blend with combustion residue or fuel at high temperatures, and it can happen almost immediately, just with a very small amount of contamination. Of course it can indicate otehr problems, but dark oil isn't really something that tells you very much all by itself.

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